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THE 
LIBRARY   OF   USEFUL   STORIES 


Hedge  Bindweed  {Convolvulus  septum). 


THE 
STORY  OF  THE   PLANTS 


BY 

GRANT    ALLEN 


WITH  MANY  ILLUSTRATIONS 


NEW    YORK 

D.    APPLETON    AND    COMPANY 

1903 


6oP'-j  2- 


Copyright,  1895,  1902, 
By  D.   APPLETON   AND   COMPANY. 


PREFACE. 


In  this  little  volume  I  have  endeavoured  to 
give  a  short  and  succinct  acgount  of  the  principal 
phenomena  of  plant  life,  in  language  suited  to 
the  comprehension  of  unscientific  readers.  As  far 
as  possible  I  have  avoided  technical  terms  and 
minute  detail,  while  I  have  tried  to  adopt  a  more 
philosophical  tone  than  is  usually  employed  in 
elementary  works.  I  have  treated  my  readers, 
not  as  children,  but  as  men  and  women,  endowed 
with  the  average  amount  of  intelligence  and  in- 
sight, and  anxious  to  obtain  some  sensible  infor- 
mation about  the  world  of  plants  which  exists  all 
round  them.  Acting  upon  this  basis,  I  have  freely 
admitted  the  main  results  of  the  latest  investiga- 
tions, accepting  throughout  the  evolutionary  the- 
ory, and  making  the  study  of  plants  a  first  intro- 
duction to  the  great  modern  principles  of  heredity, 
variation,  natural  selection,  and  adaptation  to  the 
environment.  Hence  I  have  wasted  compara- 
tively little  space  on  mere  structural  detail,  and 
have  dwelt  as  much  as  possible  on  those  more  in- 
teresting features  in  the  interrelation  of  the  plant 
and  animal  worlds  which  have  vivified  for  us  of 
late  years  the  dry  bones  of  the  old  technical 
botany. 

My  principle  has  been  to  unfold  my  subject 


\^n^ 


6  PREFACE. 

by  gradual  stages,  telling  the  reader  one  thing  at 
a  time,  and  building  up  by  degrees  his  knowledge 
of  the  subject.  My  treatment  is,  therefore,  to 
some  extent  diagrammatic,  especially  in  the  ear- 
lier chapters;  but  I  endeavour  as  I  proceed  to 
correct  the  generalisations  and  fill  in  the  gaps  of 
the  first  crude  statement.  I  trust  that  advanced 
students  who  may  glance  at  this  little  book  will 
forgive  me  for  such  concessions  to  the  weaker 
brethren,  especially  when  they  see  that  at  the 
same  time  I  have  ventured  to  lay  before  untech- 
nical  readers  all  the  latest  results  of  the  most 
advanced  botanical  research,  as  far  as  could  be 
done  in  so  small  a  compass.  I  have  even  made 
bold  to  speak  at  times  of  "carbonic  acid,"  where 
I  ought  strictly  to  have  said  "  carbon  dioxide," 
and  to  glide  gently  over  the  distinction  between 
hydro-carbons  and  carbo-hydrates,  which  could 
interest  none  but  chemical  students.  I  have  been 
well  content  to  make  these  trivial  sacrifices  of 
formal  accuracy  in  order  to  find  room  for  fuller 
exposition  of  the  delightful  relations  between 
flowers  and  insects,  birds  and  fruits,  soil  and 
plant,  climate  and  foliage.  In  one  word,  I  have 
dwelt  more  on  the  functions  and  habits  of  plants 
than  on  their  structure  and  classification.  At  the 
same  time  I  have  tried  to  lead  on  my  reader  by 
gradual  stages  to  the  further  study  of  plants  in 
the  concrete ;  and  I  shall  be  disappointed  if  my 
little  book  does  not  induce  a  considerable  pro- 
portion of  those  into  whose  hands  it  may  fall  to 
pursue  the  subject  further  in  our  fields  and  woods 
by  the  aid  of  a  Flora. 

G.  A. 
The  Croft,  Hindhead. 
Apfil,  1895. 


CONTENTS. 


CHAPTER 

I.  Introductory     .... 
II.  How  Plants  began  to  be 
HI.  How  Plants   came    to    Differ    from 

Another  

IV.  How  Plants  Eat 
V.  How  Plants  Drink  . 
VI.  How  Plants  Marry  . 
VII.  Various  Marriage  Customs 
VIII.  More  Marriage  Customs. 
IX.  The  Wind  as  Carrier 
X.  How  Flowers  Club  together 
XI.  What  Plants  do  for  their  Young 
XII.  The  Stem  and  Branches. 

XIII.  Some  Plant  Biographies 

XIV.  The  Past  History  of  Plants 


One 


PACK 

9 
14 

25 
33 
53 
73 
86 

105 
124 

135 
149 
161 
182 
203 


LIST   OF   ILLUSTRATIONS. 


FIGURE 

Hedge  Bindweed  {Convolznihis  sepiuni).  Frontispiece. 

1.  A  thin  slice  from  a  leaf,  seen  under  the  microscope 

2.  Finger-veined  leaves  .... 

3.  Feather-veined  leaves         .... 
4  and  5.  Types  of  lobed  and  divided  leaves  . 

6.  Parallel-veined  leaves         .... 

7,  8,  and  9.  Roots  of  carrot,  frogbit,  and  radish 

10.  vSundew      ....... 

11.  An  Australian  pitcher  plant 

12.  Insect-eating  pitchers  of  the  Malayan  nepenthes 
Male  and  female  flower  of  a  sedge    . 
Beginnings  of  sex  in  a  pond  weed 
Flower,  with  petals  removed,  showing  stamens  and 

pistil 

Grains  of  pollen  sending  out  pollen-tubes 
Flower  of  a  shrubbery  plant,  Weigelia 

Pin-eyed  primrose 

Thrum-eyed  primrose         .... 

20.  Male  and  female  flowers  of  arrowhead 

21.  Flower  of  water-plantain  .... 

22.  Flower  of  orchid 

Pollen-masses  of  orchid  .... 
The  two  pollen-masses,  very  much  enlarged 
The  common  arum,  or  cuckoo-pint  . 
Spike  of  the  cuckoo-pint  .... 
Male  and  female  flower  of  salad-burnet  . 
Flowers  of  bur-reed  ..... 
Flowers  of  hazel 

30  and  31.  Flowers  of  wheat    .... 

32.  Clusters  of  flowers 

33  and  34.  Florets  from  the  centre  of  a  daisy  . 

35.  Floret  from  the  ray  of  a  daisy    . 

36.  Flower-head  of  a  thistle     .... 

37.  33,  39.  40,  and  41.   Forms  of  fruits     . 
42,  43,  44,  and  45.  Floating  fruits    . 
46,  47,  and  48.     Adhesive  fruits 
49.  First  steps  in  the  evolution  of  the  stem     . 


CHAPTER  I. 

INTRODUCTORY. 

I  PROPOSE  in  this  volume  to  write  in  brief  the 
history  of  plants,  their  origin  and  their  develop- 
ment. I  shall  deal  with  them  all,  both  big  and 
little,  from  the  cedar  that  is  in  Lebanon  to  the 
hyssop  that  springeth  out  of  the  wall.  I  shall 
endeavour  to  show  how  they  first  came  into  exist- 
ence, and  by  what  slow  degrees  they  have  been 
altered  and  moulded  into  the  immense  variety  of 
tree,  shrub,  and  herb,  palm,  mushroom,  and  sea- 
weed we  now  behold  before  us.  In  short,  I  shall 
treat  the  history  of  plants  much  as  one  treats 
the  history  of  a  nation,  beginning  with  their  sim- 
ple and  unobtrusive  origin,  and  tracing  them  up 
through  varying  stages  to  their  highest  point  of 
beauty  and  efficiency. 

Plants  are  living  things.  That  is  the  first  idea 
we  must  clearly  form  about  them.  They  are  liv- 
ing in  just  the  same  sense  that  you  and  I  are. 
They  were  born  from  a  seed,  the  joint  product  of 
two  previous  individuals,  their  father  and  mother. 
Plants  likewise  live  by  eating;  they  have  mouths 
and  stomachs,  which  devour,  digest,  and  assimi- 
late the  food  supplied  to  them.  These  mouths 
and  stomachs  exist  in  the  shape  of  leaves,  whose 
business  it  is  to  catch  floating  particles  of  car- 
bonic acid  in  the  air  around,  to  suck  such  par- 
ticles in  by  means  of  countless  lips,  and  to  extract 

9 


lO        THE  STORY  OF  THE  PLANTS. 

from  them  the  carbon  which  is  the  principal  food 
and  raw  material  of  plant  life.  Plants  also  drink, 
but,  unlike  ourselves,  they  have  quite  different 
mouths  to  eat  with  and  to  drink  with.  They  take 
in  their  more  solid  constituent,  carbon,  with  their 
leaves  from  the  air  ;  but  they  take  in  their  liquid 
constituent,  water,  with  their  roots  and  rootlets 
from  the  soil  beneath  them.  "  More  solid,"  I  say, 
because  the  greater  part  of  the  wood  and  harder 
tissues  of  plants  is  made  up  of  carbon,  in  com- 
bination with  other  less  important  materials; 
though,  when  the  plants  eat  this  carbon,  it  is  not 
in  the  solid  form,  but  in  the  shape  of  a  gas,  car- 
bonic acid,  as  I  shall  more  fully  explain  when 
we  come  to  consider  this  subject  in  detail.  For 
the  present,  it  will  be  enough  to  remember  that 
Plants  are  living  things^  which  eat  and  drink  exactly 
as  we  ourselves  do. 

Plants  also  marry  and  rear  families.  They 
have  two  distinct  sexes,  male  and  female — some- 
times separated  on  different  plants,  but  more 
often  united  on  the  same  stem,  or  even  combined 
in  the  same  flower.  For  flowers  are  the  reproduc- 
tive parts  of  plants;  they  are  there  for  the  pur- 
pose of  producing  the  seeds,  from  which  new 
plants  spring,  and  by  means  of  which  each  kind 
is  perpetuated.  The  male  portions  of  plants  of 
the  higher  types  are  known  as  stamens;  they  shed 
a  yellow  powder  which  we  call  polleft,  and  this 
powder  has  a  fertilising  influence  on  the  young 
seeds  or  ovules.  The  female  portion  of  plants  of 
the  higher  types  is  known  as  the  pistil;  it  con- 
tains tiny  undeveloped  knobs  or  ovules,  which 
can  only  swell  out  and  grow  into  fruitful  seeds 
provided  they  have  been  fertilised  by  pollen  from 
the   stamens  of  their  own  or  some  other  flower. 


INTRODUCTORY.  II 

The  ovules  thus  answer  very  closely  to  the  eggs 
of  animals.  After  they  have  been  fertilised,  the 
pistil  begins  to  mature  into  what  we  call  a  fruity 
which  is  sometimes  a  sweet  and  juicy  berry,  as  in 
the  grape  or  the  currant,  but  more  often  a  dry 
capsule,  as  in  the  poppy  or  the  violet. 

Plants,  however,  unlike  animals,  are  usually 
fixed  and  rooted  to  one  spot.  This  makes  it 
practically  impossible  for  them  to  go  in  search 
of  mates,  like  birds  or  butterflies,  squirrels  or 
weasels.  So  they  are  obliged  to  depend  upon 
outside  agencies,  not  themselves,  for  the  convey- 
ance of  pollen  from  one  flower  to  another.  Some- 
times, in  particular  plants,  such  as  the  hazels  and 
grasses,  it  is  the  wind  that  carries  the  pollen  on 
its  wings  from  one  blossom  to  its  neighbour;  and, 
in  this  case,  the  stamens  which  shed  the  pollen 
hang  out  freely  to  the  breeze,  while  the  pistil, 
which  is  to  catch  it,  is  provided  with  numberless 
little  feathery  tails  to  receive  the  passing  grains 
of  fertilising  powder.  But  oftener  still,  it  is  in- 
sects that  perform  this  kind  oflice  for  the  plant, 
as  in  the  dog-rose,  the  hollyhock,  and  the  greater 
part  of  our  beautiful  garden  flowers.  In  such 
cases  the  plant  usually  makes  its  blossom  very 
attractive  with  bright-coloured  petals,  so  as  to 
allure  the  insect,  while  it  repays  him  for  his 
trouble  in  carrying  away  the  pollen  by  giving  him 
in  return  a  drop  of  honey.  The  bee  or  butterfly 
goes  there,  of  course,  for  the  honey  alone,  un- 
conscious that  he  is  aiding  the  plant  to  set  its 
seeds;  but  the  plant  puts  the  honey  there  in 
order  to  entice  him  against  his  will  to  transport 
the  fertilising  powder  from  flower  to  flower. 
There  is  no  more  fascinating  chapter  in  the  great 
book  of  life  than  that  which  deals  with  these  mar- 


12        THE  STORY  OF  THE  PLANTS. 

riage  relations  of  the  flowers  and  insects,  and  I 
shall  explain  at  some  detail  in  later  portions  of 
this  little  work  some  of  the  most  curious  and  in- 
teresting of  such  devices. 

Again,  after  the  plant  has  had  its  flower  ferti- 
lised, and  has  set  its  seed,  it  has  to  place  its  young 
ones  out  in  the  world  to  the  greatest  advantage. 
If  it  merely  drops  them  under  its  own  branches, 
they  may  not  thrive  at  all ;  it  may  have  im- 
poverished the  soil  already  of  certain  things 
which  are  necessary  for  that  particular  kind,  ow- 
ing to  causes  to  be  explained  hereafter;  and  even 
where  this  is  not  the  case,  the  surrounding  soil 
may  be  so  fully  occupied  by  other  plants  that  the 
poor  little  seedlings  get  no  chance  of  establishing 
themselves.  To  meet  such  emergencies,  plants 
have  invented  all  sorts  of  clever  dodges  for  dis- 
persing their  seeds,  into  the  nature  of  which  we 
will  go  in  full  in  the  sequel.  Thus,  some  of  them 
put  feathery  tops  to  their  seeds  or  fruits,  like  the 
thistle  and  the  dandelion,  the  willow  and  the 
cotton-bush,  by  means  of  which  they  float  lightly 
on  the  air,  and  are  wafted  by  the  wind  to  new 
and  favourable  situations.  Others,  again,  bribe 
animals  to  disperse  them,  by  the  allurement  of 
sweet  and  pulpy  fruits,  like  the  strawberry  or  the 
orange;  and  in  all  these  instances,  though  the 
fruit  or  outer  coat  is  edible,  the  actual  seed  itself 
is  hard  and  indigestible,  like  the  orange-pip,  or 
is  covered  with  a  solid  envelope  like  the  cherry- 
stone. Numerous  other  examples  we  shall  see 
by  and  by  in  their  proper  place.  For  the  present, 
we  have  only  to  remember  that  plants  to  some 
extent  provide  beforehand  for  their  children,  and 
in  many  cases  take  care  to  set  them  out  in  life  to 
the  best  possible  advantage. 


INTRODUCTORY.  I3 

Most  of  these  points  to  which  I  am  here 
briefly  calHng  your  attention  are  true  only  of  the 
higher  plants,  and  especially  of  land-plants.  For 
we  must  not  forget  that  plants,  like  animals,  differ 
immensely  from  one  another  in  dignity,  rank,  and 
relative  development.  There  are  higher  and 
lower  orders.  We  shall  have  to  consider,  there- 
fore, their  grades  and  classes — to  find  out  why 
some  are  big,  some  small ;  some  annual,  some 
perennial  ;  why  some  are  rooted  in  dry  land,  while 
some  float  freely  about  in  water ;  why  some  have 
soft  stems  like  spinach  and  celery,  while  others 
have  hard  trunks  like  the  oak  and  the  chestnut. 
We  shall  also  have  to  ask  ourselves  what  were 
the  causes  which  made  them  differ  at  first  from 
one  another,  and  to  what  agencies  they  owe  the 
various  steps  in  their  upward  development.  In 
short,  we  must  not  rest  content  with  merely  say- 
ing that  the  rose  is  like  this  and  the  cabbage  like 
that ;  we  must  try  to  find  out  what  gave  to  each 
of  them  its  main  distinctive  features.  We  must 
"consider  the  lilies,  how  they  grow,"  and  must 
seek  to  account  for  their  growth  and  their  pecul- 
iarities. 

And  now  let  me  sum  up  again  these  central 
ideas  of  our  future  reading  on  plants  and  their 
history. 

Plants  are  living  things ;  they  eat  with  their 
leaves,  and  drink  with  their  rootlets.  They  take 
up  carbon  from  the  air,  and  water  from  the  soil, 
and  build  the  materials  so  derived  into  their  own 
bodies.  Plants  also  marry  and  are  given  in  mar- 
riage. They  have  often  two  sexes,  male  and 
female.  Each  seed  is  thus  the  product  of  a 
separate  father  and  mother.  Plants  are  of  many 
kinds,  and  we  must  inquire  by  and  by  how  they 


14        THE  STORY  OF  THE  PLANTS. 

came  to  be  so.  Plants  live  on  sea  and  land,  and 
have  varieties  specially  fitted  for  almost  every 
situation.  Plants  have  very  varied  ways  of  secur- 
ing the  fertilisation  of  their  flowers,  and  look 
after  the  future  of  their  young,  like  good  parents 
that  they  are,  in  many  different  manners.  Plants 
are  higher  and  lower,  exactly  like  animals. 

These  are  some  of  the  points  we  must  proceed 
to  consider  at  greater  length  in  the  following 
pages. 


CHAPTER    II. 

HOW    PLANTS    BEGAN    TO    BE. 

Which  came  first — the  plant  or  the  animal  ? 

That  question  is  almost  as  absurd  as  if  one 
were  to  ask.  Which  came  first — the  beast  of  prey, 
or  the  animals  it  preys  upon  ?  Clearly,  the  ear- 
liest animals  could  not  possibly  have  been  lions 
and  tigers;  for  lions  and  tigers  could  not  begin 
to  exist  till  after  there  were  deer  and  antelopes 
for  them  to  hunt  and  devour.  Now  the  general  con- 
nection between  animals  and  plants  is  somewhat 
the  same  in  this  respect  as  the  general  connection 
between  beasts  of  prey  and  the  creatures  they 
feed  upon.  For  all  animals  feed,  directly  or  in- 
directly, upon  plants  and  their  products.  Even 
carnivorous  animals  eat  sheep  and  rabbits,  let  us 
say ;  but  then,  the  sheep  and  the  rabbits  eat  grass 
and  clover.  In  the  last  resort,  plants  are  self- 
supporting  ;  animals  feed  upon  what  the  plants 
have  laid  by  for  their  own  uses.  Every  animal 
gets  all  its  material  (except  water)  directly  or  in- 
directly from  plants.     In  one  v^oxd,  J^lafits  are  the 


HOW    PLANTS    BEGAN    TO    BE.  15 

only  things  that  know  ho7v  to  manufacture  living  vui- 
terial. 

Roughly  speaking,  plants  are  the  producers 
and  animals  the  consumers.  Plants  are  like  the 
pine-tree  that  makes  the  wood ;  animals  are  like 
the  fire  that  burns  it  up  and  reduces  it  to  its  pre- 
vious unorganised  condition. 

It  is  a  little  difficult  really  to  understand  the 
true  relation  of  plants  and  animals  without  some 
small  mental  effort;  yet  the  point  is  so  important, 
and  will  help  us  so  much  in  our  after  inquiries, 
that  I  will  venture  upon  asking  you  to  make  that 
effort,  here  at  the  very  outset. 

If  you  take  a  piece  of  wood  or  coal,  you  have 
in  it  a  quantity  of  hydrogen  and  carbon,  almost 
unmixed  with  oxygen,  or  at  least  combined  with 
far  less  oxygen  than  they  are  capable  of  uniting 
with.  Now  put  a  light  to  the  wood  or  coal,  and 
what  happens  ?  They  catch  fire,  as  we  say,  and 
burn  till  they  are  consumed.  And  what  is  the 
meaning  of  this  burning  ?  Why,  the  carbon  and 
hydrogen  are  rushing  together  with  oxygen — 
taking  up  all  the  oxygen  they  can  unite  with,  and 
forming  with  it  carbonic  acid  and  water.  The 
carbon  joins  the  oxygen  in  a  very  close  embrace, 
and  becomes  carbonic  acid  gas,  which  goes  up  the 
chimney  and  mixes  with  the  atmosphere;  the 
hydrogen  joins  the  oxygen  in  an  equally  intimate 
union,  and  similarly  goes  off  into  the  air  in  the 
form  of  steam  or  watery  vapour.  Burning,  in 
fact,  is  nothing  more  than  the  union  of  the  carbon 
and  hydrogen  in  wood  or  coal  with  the  oxygen  of 
the  atmosphere.  But  observe  that,  as  the  carbon 
and  hydrogen  burn,  they  give  off  light  and  heat. 
This  light  and  heat  they  held  stored  up  before  in 
their  separate  form ;  it  was,  so  to  speak,  dormant 


1 6  THE   STORY   OF   THE   PLANTS. 

or  latent  within  them.  Free  carbon  and  free 
hydrogen  contain  an  amount  of  energy^  that  is  to 
say  of  latent  light  and  dormant  heat,  which  they 
yield  up  when  they  unite  with  free  oxygen.  And 
though  the  carbon  and  hydrogen  in  wood  and  coal 
are  not  quite  free,  they  may  be  regarded  as  free 
for  our  present  purpose. 

Now,  where  did  this  light  and  heat  come  from  ? 
Well,  the  wood,  we  know,  is  part  of  a  tree  which 
has  grown  in  the  open  air,  by  the  aid  of  sunshine. 
The  coal  is  just  equally  part  of  certain  very 
ancient  plants,  long  pressed  beneath  the  earth 
and  crushed  and  hardened,  but  still  possessing 
the  plant-like  property  of  burning  when  lighted. 
In  both  cases  the  light  and  heat,  as  we  shall  see 
more  fully  hereafter,  are  derived  from  the  sun, 
our  great  storehouse  of  energy.  The  sunshine 
fell  upon  the  leaves  of  the  modern  oak-tree,  or  of 
the  very  antique  club-mosses  which  constitute 
coal,  and  separated  in  them  the  carbon  from  the 
oxygen  of  carbonic  acid,  and  the  hydrogen  from 
the  oxygen  of  the  water  in  the  sap.  In  each  case 
the  oxygen  was  turned  loose  upon  the  air  in  its 
free  form,  while  the  carbon  and  'the  hydrogen 
(with  a  very  little  oxygen  and  a  few  other  ma- 
terials) were  left  in  loose  and  almost  free  condi- 
tions in  the  leaves  and  wood  of  the  oak  or  the  club- 
moss.  But  the  point  to  which  I  wish  now  specially 
to  direct  your  attention  is  this — the  sunlight  was 
actually  used. up  for  the  time  being  in  effecting 
this  separation  between  the  oxygen  on  the  one 
hand,  and  the  carbon  and  hydrogen  on  the  other. 
As  long  as  the  plant  remained  unburnt,  the  light 
and  heat  it  received  from  the  sun  lay  dormant 
within  it,  not  as  actual  light  and  heat,  but  as  sepa- 
ration between  the  oxygen  and  the  hydrogen  or 


HOW    PLANTS   BEGAN   TO   BE.  17 

carbon.  Coal,  indeed,  has  been  well  described  as 
*'  bottled  sunshine." 

More  than  this;  it  took  just  as  much  light  and 
heat  from  the  sun  to  build  up  the  plant  as  you 
can  get  out  of  the  plant  in  the  end  by  burning  it. 

Now,  let  us  burn  our  pieces  of  wood  or  coal, 
and  what  happens  ?  Why,  particles  of  oxygen 
rush  together  with  particles  of  carbon  in  the  fuel, 
and  form  carbonic  acid.  How  much  carbonic 
acid  ?  Just  as  much  as  it  took  originally  to  build 
that  part  of  the  plant  from.  Simultaneously, 
other  particles  of  oxygen  in  the  air  rush  together 
with  particles  of  hydrogen  in  the  fuel,  and  form 
water,  in  the  shape  of  steam.  How  much  water  ? 
Just  as  much  as  it  took  originally  to  build  that 
part  of  the  plant  from.  As  they  unite,  they  give 
out  their  dormant  heat  and  light.  How  much 
heat  and  light?  Just  as  much  as  they  absorbed 
in  the  act  of  building  up  those  parts  of  the  plant 
from  the  sunshine  that  fell  upon  them. 

In  other  words,  the  same  quantity  of  oxygen 
that  was  first  separated  from  the  carbon  and  hy- 
drogen reunites  with  them  in  the  act  of  burning, 
and  the  same  amount  of  heat  and  light  that  were 
required  to  effect  their  separation  is  yielded  up 
again  in  the  act  of  reunion. 

Let  us  put  this  point  numerically,  and  I  will 
simplify  it  exceedingly,  so  as  to  make  my  meaning 
clearer.  Suppose  we  begin  with  a  particle  of 
carbonic  acid  and  a  particle  of  water  in  the  inte- 
rior of  a  green  leaf — the  carbonic  acid  swallowed 
from  the  air  by  the  leaf,  the  water  brought  to  it 
as  sap  from  the  roots.  Now,  under  the  influence 
of  sunlight,  these  materials  are  separated  into 
their  component  parts.  The  particle  of  carbonic 
acid  consists  of  one  atom  of  carbon,  closely  locked 


1 8  THE   STORY  OF  THE   PLANTS. 

up  with  two  atoms  of  oxygen.  It  takes  an  amount 
of  sunlight,  which  we  will  call  A,  to  unlock  this 
union,  and  separate  the  atoms.  The  oxygen  goes 
off  free  into  the  air,  and  the  carbon  remains  in  the 
leaf  as  material  for  building  the  plant  up.  Again, 
the  particle  of  water  consists  of  two  atoms  of 
hydrogen,  closely  locked  up  with  one  atom  of 
oxygen.  It  takes  an  amount  of  sunlight,  which 
we  will  call  B,  to  unlock  this  union  and  separate 
the  atoms.  The  oxygen  once  more  goes  off  free 
into  the  air,  and  the  hydrogen  joins  in  a  loose 
union  with  the  carbon  already  spoken  of.  Now, 
burn  the  materials  resulting  from  these  two  acts, 
and  what  happens  ?  Two  atoms  of  oxygen  once 
more  unite  with  the  one  atom  of  carbon,  to  form 
a  particle  of  carbonic  acid ;  one  atom  of  oxygen 
once  more  unites  with  the  two  atoms  of  hydrogen 
to  form  a  particle  of  water,  and  there  is  given  out 
in  the  act  of  union  an  amount  of  light  and  heat 
exactly  equal  to  the  A  and  B  originally  locked  up 
in  the  act  of  separating  them. 

I  have  now  made  it  clear,  I  hope,  what  plant 
life  really  is  in  its  final  essence.  In  nature  at 
large,  the  elements  which  chiefly  compose  it — 
namely,  carbon  and  hydrogen — exist  only  in  very 
close  union  with  oxygen  ;  the  plant  is  a  machine 
for  separating  these  elements  from  oxygen  under 
the  influence  of  sunlight,  and  building  them  up 
into  fresh  forms,  whose  great  peculiarity  is  that 
they  possess  energy  or  dormant  motion. 

Now  the  animal  is  the  exact  opposite  of  all 
this.  He  is  essentially  a  destroyer,  as  the  plant 
is  a  builder.  The  plant  produces;  the  animal 
consumes;  the  plant  makes  living  matter,  the 
animal  breaks  it  down  again.  He  is,  in  fact,  a 
slow  fire,  where  plant  products  like  grasses,  fruits. 


HOW   PLANTS   BEGAN   TO   BE.  19 

nuts,  or  grains,  are  consumed  by  degrees  and  re- 
duced once*more  to  their  original  condition. 

The  animal  eats  what  the  plant  laid  by.  He 
also  breathes — that  is  to  say,  takes  oxygen  into 
his  lungs.  Within  his  body  that  oxygen  once 
more  unites  with  the  carbon  and  the  hydrogen, 
and  is  given  out  again  in  union  with  them  as 
carbonic  acid  and  water.  And  the  energy  in  the 
plant  food,  thus  set  free  within  his  body,  takes 
the  form  of  animal  heat  and  animal  motion — just 
as  the  energy  set  free  in  the  locomotive  takes 
the  form  of  heat  and  visible  movement.  Animals 
are  thus  the  absolute  converse  of  plants;  all  that 
the  plants  did,  the  animal  undoes  again. 

Briefly  to  recapitulate  this  rather  dry  subject, 
— the  plant  is  a  mechanism  for  separating  oxygen 
from  carbon  and  hydrogen,  and  for  storing  up 
sun-energy.  The  animal  is  a  mechanism  for 
uniting  oxygen  with  carbon  and  hydrogen,  and 
for  using  the  stored-up  sun-energy  as  heat  and 
motion. 

And  now  you  can  see  why  it  is  so  absurd  to 
ask.  Which  came  first,  the  plant  or  the  animal  ? 
You  might  as  well  ask.  Which  came  first,  the  coal 
or  the  fire  ?  All  the  living  material  in  the  world 
was  first  made  and  laid  up  by  plants.  They  alone 
have  the  power  to  make  living  or  energy-yielding 
stuff  out  of  dead  and  inert  water  or  carbonic  acid. 
They  are  the  origin  and  foundation  of  life.  With- 
out them  there  could  be  no  living  thing  in  the 
universe.  It  is  in  their  green  parts  alone  that 
the  wonderful  transformation  of  dead  matter  into 
living  bodies  takes  place;  they  alone  know  how 
to  store  up  and  utilise  the  sunshine  that  falls 
upon  them.     All  the  animal  can  do  is  to  take  the 


20  THE   STORY  OF  THE   PLANTS. 

living  material  the  plant  has  made  for  him,  and 
to  consume  it  slowly  in  his  own  bod^.  He  de- 
stroys it  (as  living  matter)  just  as  truly  as  a  fire 
does,  and  turns  it  loose  on  the  air  again  in  the 
dead  and  inert  forms  of  water  and  carbonic  acid. 
It  is  clear,  then,  that  plants  must  have  come 
first,  and  animals  afterward.  The  earliest  living 
beings  must  needs  have  been  plants — very  simple 
plants ;  yet  essentially  plants  in  this — that  they 
were  green,  and  that  they  separated  carbon  and 
hydrogen  from  oxygen  under  the  influence  of 
sunlight.  It  is  that  above  everything  that  makes 
true  plants ;  though  some  degenerate  plants  have 
now  given  up  their  ancestral  habit,  and  behave  in 
this  respect  much  like  animals. 

How  did  the  first  plant  of  all  come  into 
being  ? 

About  that,  at  present,  we  know  very  little. 
We  can  only  guess  that,  in  the  early  ages  of  the 
world,  w^hen  matter  was  fresher  and  more  plastic 
than  now,  certain  combinations  were  set  up  be- 
tween atoms  under  the  influence  of  sunlight, 
which  formed  the  earliest  living  body.  This 
would  be  what  is  called  ''spontaneous  genera- 
tion." Whether  such  spontaneous  generation 
ever  took  place  is  much  disputed  ;  though  some 
people  competent  to  form  an  opinion  incline  to 
believe  that  it  probably  did  take  place  in  remote 
times  and  under  special  conditions.  But  it  is 
certain,  or  almost  certain,  that  in  our  own  days 
at  least  spontaneous  generation  does  not  take 
place — perhaps  because  all  the  available  material 
is  otherwise  employed,  perhaps  because  the  con- 
ditions are  no  longer  favourable.  At  any  rate, 
we  have    every   reason   to    suppose   that   at   the 


HOW   PLANTS   BEGAN   TO   BE.  21 

present  day  every  living  being,  whether  plant  or 
animal,  is  the  product  of  a  previous  living  being, 
its  parent,  or  of  two  previous  living  beings,  its 
father  and  mother. 

Why  should  this  be  so?  Well,  if  you  think 
for  a  moment,  you  will  see  that  it  results  almost 
naturally  from  the  other  facts  we  have  so  far 
considered.  For  the  plant  is  a  machine  for  mak- 
ing living  matter  out  of  water  and  carbonic  acid, 
under  the  influence  of  sunlight.  As  long  as  sun- 
light, direct  or  reflected,  in  sun  or  shade,  falls 
upon -a  green  plant,  the  plant  goes  on  taking  up 
carbonic  acid  from  the  air  by  means  of  its  leaves, 
and  water  from  the  earth  by  means  of  its  roots, 
and  continues  to  manufacture  from  them  fresh 
living  material.  Thus  it  must  be  always  growifig, 
as  we  say ;  in  other  words,  the  mass  of  living 
material  must  be  constantly  increasing.  Now,  it 
results  from  this  that  the  plant  would  grow  in 
time  unwieldily  large;  and  in  simple  types,  when 
it  grows  very  large,  it  splits  or  divides  into  two 
portions.  That  is  the  real  origin  of  what  we  call 
REPRODUCTION.  In  its  simplest  forms,  reproduc- 
tion means  no  more  than  this — that  a  rather 
large  body,  which  cannot  easily  hold  together, 
divides  in  two,  and  that  each  part  of  it  then  con- 
tinues to  live  and  grow  exactly  as  the  whole  did. 

This  seems  odd  and  unfamiliar  to  you,  because 
you  are  thinking  of  large  and  very  advanced 
plants,  like  a  sweet-pea  or  a  potato.  But  you 
must  remember  that  we  are  dealing  here  with 
very  early  and  simple  plants,  and  that  these  early 
and  simple  plants  consist  for  the  most  part  of 
tiny  green  mites,  floating  free  in  water.  They 
are  generally  invisible  to  the  naked  eye,  and  are 
in  point  of  fact  mere  specks  of  green  jelly.     Yet 


22  THE   STORY   OF   THE   PLANTS. 

it  is  from  such  insignificant  atoms  as  these  that 
the  great  forest  trees  derive  their  origin,  through 
a  long  line  of  ancestors;  and  if  we  wish  to  under- 
stand the  larger  and  more  developed  plants,  we 
must  begin  by  understanding  these  their  simple 
relations. 

Very  early  plants,  then,  floated  free  in  water; 
and  there  is  reason  to  believe  that  for  a  consider- 
able period  in  the  beginnings  of  our  world  there 
was  no  dry  land  at  all ;  the  whole  surface  of  the 
globe  was  covered  by  one  boundless  ocean.  At 
any  rate,  most  of  the  simplest  and  earliest  forms 
of  life  now  remaining  to  us  inhabit  the  water, 
either  fresh  or  salt ;  while  almost  all  the  higher 
and  nobler  plants  and  animals  are  dwellers  on 
land.  Hence  it  is  not  unreasonable  to  conclude 
that  life  began  i?i  the  sea,  and  only  gradually  spread 
itself  over  the  islands  and  continents. 

Floating  jelly-like  plants  would  readily  reach 
a  size  at  which  it  would  be  convenient  for  them 
to  split  in  two — or  rather,  at  which  it  would  be 
difficult  for  them  to  hold  together  ;  and  most  very 
small  floating  plants  do  to  this  day  continue  to 
grow,  up  to  a  certain  point,  and  then  divide  into 
two  similar  and  equal  portions.  This  is  the  sim- 
plest known  form  of  what  we  call  reproduction. 
Of  course,  the  two  halves  into  which  the  plant 
thus  divides  itself  are  exactly  like  one  another; 
and  that  gives  us  the  basis  for  what  we  call  he- 
redity— that  is  to  say,  the  general  similarity 
between  parent  and  offspring.  This  similarity  de- 
pends upon  the  fact  that  the  two  were  once  one, 
and  when  they  split  or  divide  each  part  continues 
to  possess  all  the  qualities  of  the  original  mass  of 
which  it  once  formed  a  portion. 

You  will   observe   that   I   here  use  the  words, 


HOW   PLANTS   BEGAN   TO   BE.  23 

parent  and  offspring.  I  do  so,  partly  from  cus- 
tom, and  partly  to  show  where  this  reasoning  leads 
us.  But  in  reality,  in  such  very  simple  plants, 
neither  part  of  the  divided  whole  can  claim  to  be 
either  parent  or  child  ;  they  are  equal  and  similar. 
In  higher  plants,  however  (as  in  higher  animals), 
we  find  that  the  main  portion  of  the  plant  con- 
tinues to  live  and  grow,  and  sends  off  smaller  por- 
tions, known  as  spores  or  seeds,  to  reproduce  its 
species.  Here,  we  may  fairly  speak  of  the  larger 
plant  as  the  parent,  and  of  the  smaller  ones  which 
it  detaches  from  itself  as  its  children  or  offspring. 

The  truth  is,  every  gradation  exists  in  nature 
between  these  two  extreme  cases.  The  different 
types  glide  imperceptibly  into  one  another.  There 
is  no  one  point  at  which  we  can  definitely  say, 
"  Here  reproduction  by  splitting  or  division  ceases, 
and  reproduction  by  eggs,  or  by  spores  or  seeds 
begins." 

Again,  all  the  earlier  and  simpler  plants  are 
sexless;  they  simply  grow  till  they  divide,  and 
then  the  two  halves  continue  to  exist  independ- 
ently. No  two  distinct  plants  or  parts  of  plants 
are  concerned  in  producing  each  new  individual. 
But  the  higher  plants,  like  the  higher  animals, 
are  male  and  female.  In  such  cases  two  distinct 
individuals  combine  to  form  a  new  one.  They 
are  its  father  and  mother,  so  to  speak,  and  the 
young  one  is  their  offspring.  A  little  grain  of 
pollen  produced  by  the  male  plant  unites  with  a 
little  ovule  or  seedlet  produced  by  the  female ; 
and  from  the  union  of  the  two  springs  a  fresh 
young  plant,  deriving  its  peculiarities  about  equal- 
ly from  each  of  them.  How  and  why  this  great 
change  in  the  mode  of  reproduction  takes  place 
is  another  of  the  questions  we  must  discuss  here- 


24  THE    STORY   OF   THE    PLANTS. 

after ;  I  will  only  anticipate  now  the  result  of 
this  discussion  by  saying  briefly  beforehand  that 
plants  gain  in  this  way,  because  greater  variety  is 
secured  in  the  offspring,  and  because  the  weak 
points  of  one  parent  are  likely  to  be  reinforced 
and  made  good  by  the  other. 

Let  us  sum  up  our  conclusions  in  this  pre- 
liminary chapter  : — 

Plants  are  an  older  type  of  life  than  animals. 
They  are  the  first  and  most  original  form  of  liv- 
ing beings,  and  without  them  no  life  of  any  sort 
would  be  possible.  All  living  matter  is  manufac- 
tured by  plants  out  of  material  found  floating  in 
the  air,  under  the  influence  of  sunlight.  How 
plants  first  came  into  existence  we  do  not  yet 
know  ;  but  we  may  siispect  that  they  grew,  in  very 
simple  and  small  forms,  at  a  remote  period,  under 
conditions  which  now  no  longer  exist.  It  is  al- 
most certain  that  the  first  plants  were  jelly-like 
specks,  floating  freely  in  water.  They  must  have 
been  green,  and  must  also  have  possessed  the 
essential  plant-power  of  building  up  fresh  living 
material  when  sunlight  fell  upon  them.  This  pow- 
er implies  the  other  power  of  reproduction,  that  is 
to  say  of  splitting  up  into  two  or  more  similar 
parts,  each  of  which  continues  to  live  and  grow 
like  the  original  body.  From  such  simple  and 
very  primordial  plants  all  other  and  higher  forms 
are  most  likely  descended. 


HOW   PLANTS   CAME   TO   DIFFER. 


CHAPTER    III. 

HOW    PLANTS    CAME    TO    DIFFER    FROM    ONE 
ANOTHER. 

All  plants  are  not  now  alike.  Some  are  trees, 
some  herbs ;  some  are  roses,  some  buttercups. 
Yet  we  have  a  certain  amount  of  reason  to  believe 
that  they  are  all  descended  from  one  and  the 
same  original  ancestor ;  and  we  shall  see  by  and 
by  that  we  can  often  trace  the  various  stages  in 
their  long  development.  They  differ  immensely. 
Some  of  them  are  more  advanced  and  more  com- 
plex than  their  neighbours;  some  are  small  and 
low,  while  others  are  tall  and  strong;  some,  like 
nettles  and  grasses,  have  simple  and  inconspicu- 
ous flowers,  while  others,  like  lilies  and  orchids, 
have  beautiful  and  very  complicated  blossoms, 
highly  arranged  in  such  ways  as  to  attract  and 
entice  particular  insects  to  visit  and  fertilise  them. 
Again,  some  have  tiny  dry  fruits,  with  small  round 
seeds,  which  fall  on  the  ground  unheeded ;  while 
others  have  brilliant  red  or  yellow  berries,  or 
winged  or  feathery  seeds,  especially  fitted  for  spe- 
cial modes  of  dispersion.  In  short,  there  are 
plants  which  seem,  as  it  were,  very  low  and  un- 
civilised, while  there  are  others  which  display,  so 
to  speak,  all  the  latest  modern  inventions  and 
improvements. 

The  question  is,  How  did  they  thus  come  to 
differ  from  one  another  ?  What  made  them  vary 
in  such  diverse  ways  from  the  primitive  pattern  ? 

In  order  to  understand  the  answer  which 
modern  science  gives  to  this  question,  we  must 
first  glance  briefly  at  certain  early  steps  in  the 


26  THE   STORY   OF  THE   PLANTS. 

history  of  the  process  which  we  call  creation  or 
evolution. 

The  earliest  plants,  we  saw,  were  in  all  prob- 
ability mere  tiny  green  jelly-specks,  floating  free 
in  water,  and  taking  from  it  small  quantities  of 
dissolved  carbonic  acid,  which  they  manufactured 
for  themselves  into  green  living  material  when 
sunlight  fell  upon  them.  Now  we  shall  have  to 
consider  another  peculiarity  of  plants  (and  of 
animals  as  well  before  we  can  thoroughly  under- 
stand the  first  stage  in  the  upv>ard  process  which 
leads  at  last  to  the  pine  and  the  lily,  the  palm 
and  the  apple. 

Plants  are  made  up  of  separate  parts  or  ele- 
ments, known  as  ce//s,  each  of  which  consists  of  a 
thin  cell-wall,  usually  containing  living  material. 
The  very  simplest  and  earliest  plants,  however, 
consist  of  a  single  such  cell  apiece;  they  are 
specks  of  green  jelly,  enclosed  by  a  cell-wall, 
alone  and  isolated.  In  such  cases,  when  the  cell 
grows  big  and  divides  in  two,  each  half  floats  off 
as  a  separate  cell,  or  a  separate  plant,  and  con- 
tinues to  divide  again  and  again,  as  long  as  it  can 
get  a  sufficient  amount  of  carbonic  acid  and  sun- 
light. But  in  some  instances  it  happens  that  the 
new  cells,  when  budded  out  from  the  old  ones,  do 
not  float  off  in  water,  but  remain  hanging  to- 
gether in  long  strings  or  threads,  in  single  file,  as 
you  may  see  in  certain  simple  forms  of  hair-like 
pond-weeds.  These  weeds  consist  of  rows  of 
cells,  stuck  one  after  another,  not  unlike  rows  of 
pearls  in  a  necklace.  Of  course  the  individual 
cells  are  too  small  to  see  with  one's  unaided  eye  ; 
but  under  a  microscope  you  can  see  them,  joined 
end  to  end,  so  as  to  form  a  sort  of  thread  or  long 


HOW   PLANTS   CAME   TO   DIFFER.  27 

line  of  plant-cells.  This  is  the  beginning  of  the 
formation  of  the  higher  plants,  which  consist,  in- 
deed, of  collections  of  cells,  arranged  either  in 
rows  or  in  flattened  blades,  or  many  deep  together 
in  complicated  order. 

However,  the  higher  plants  differ  from  the 
lower  ones  in  something  more  than  the  number 
and  complexity  of  the  cells  which  comipose  them. 
They  are  very  varied ;  and  their  variety  adapts 
them  to  their  special  circumstances.  For  example, 
desert  plants,  like  the  cactuses,  have  thick  and 
fleshy  leaves  (or,  rather,  jointed  stems)  to  store 
up  water,  with  a  very  tough  skin  to  prevent 
evaporation.  The  flowers  of  each  country,  again, 
are  exactly  adapted  to  the  insects  of  that  coun- 
try ;  and  so  are  the  fruits  to  the  birds  that  swal- 
low and  disperse  them.  How  did  this  all  come 
about  ?  What  made  the  adaptation  ?  It  is  a  re- 
sult of  two  great  underlying  principles  known  as 
The  Struggle  for  Life,  and  Natural  Selection. 

Since  each  early  plant  goes  on  growing  and 
dividing,  again  and  again,  as  fast  as  it  can,  it 
must  follow  in  time  that  a  great  number  of  plants 
will  soon  be  produced,  each  fighting  with  the 
others  for  air  and  sunlight.  Now,  some  of  them 
must,  by  pure  accident  of  situation,  get  better 
placed  than  others;  and  these  will  produce  greater 
numbers  of  descendants.  Again,  unless  all  of 
them  remained  utterly  uninfluenced  by  circum- 
stances (which  is  not  likely)  it  must  necessarily 
happen  that  slight  dift'erences  will  come  to  exist 
between  them.  These  differences  of  outline,  or 
shape,  or  cell-wall,  may  happen  to  make  it  easier 
or  harder  for  the  plant  to  get  access  to  carbonic 
acid  and  sunlight,  or  to  disperse  its  young,  or  to 
fix   itself    favourably.     Those    plants,    therefore, 


28  THE   STORY  OF   THE   PLANTS. 

which  happened  to  vary  in  the  right  directions 
would  most  easily  go  on  living  and  produce  most 
descendants,  while  those  which  happened  to  vary 
in  the  wrong  directions  would  soonest  die  out  and 
leave  fewest  descendants. 

Well,  the  world  around  us,  both  of  plants  and 
animals,  is  full  of  creatures  all  struggling  against 
one  another,  and  all  competing  for  food  and  air 
and  sunshine.  Moreover,  each  individual  pro- 
duces (as  a  rule)  a  vast  number  of  young;  some- 
times, like  the  poppy,  many  thousand  seeds  on  a 
single  flower-stem.  Now  suppose  only  ten  of 
those  seeds  succeed  in  growing  each  year.  In  the 
first  year,  that  poppy  will  have  produced  ten  new 
poppy  plants;  the  year  after,  each  of  those  ten 
will  have  produced  ten  more,  making  the  total 
loo;  in  the  third  year,  they  will  be  i,ooo;  in  the 
fourth,  10,000 ;  and  so  on  in  the  same  progression 
till  in  a  very  few  years  the  whole  world  would 
simply  be  full  of  poppies.  And  similarly  with 
animals.  If  every  egg  in  a  cod's  roe  developed 
into  a  mature  fish,  the  sea  would  soon  be  one  solid 
and  compact  mass  of  cod-fish. 

Why  doesn't  this  happen  ?  Because  every 
other  kind  is  producing  seeds  or  eggs  at  about 
the  same  rate,  and  every  one  of  them  is  fighting 
against  the  other  for  its  share  of  light  and  food 
and  soil  and  water.  The  stronger  or  better- 
adapted  survive,  while  the  weaker  or  less-adapted 
go  to  the  wall,  and  are  starved  out  of  existence. 
At  first,  to  be  sure,  it  sounds  odd  to  talk  of  a 
Struggle  for  Life  among  plants,  which  seem  too 
fixed  and  inert  to  battle  against  one  another.  But 
they  (/o  battle  for  all  that.  Each  root  is  striving 
with  all  its  might  to  fix  itself  underground  in  the 
best  position  ;  each   leaf  and   stem  is  struggling 


HOW   PLANTS   CAME   TO   DIFFER.  29 

hard  to  overtop  its  neighbour,  and  secure  its  fair 
share  of  carbon  and  of  sunshine.  When  a  garden 
is  abandoned,  you  can  very  soon  see  the  result  of 
this  struggle ;  for  the  flowers,  which  we  only  keep 
alive  by  weeding — that  is  to  say,  by  uprooting 
the  sturdier  competitors — are  soon  overgrown 
and  killed  out  by  the  weeds — that  is  to  say,  by 
the  stronger  and  better-adapted  native  plants  of 
the  district. 

This,  then,  is  the  nature  and  meaning  of  these 
two  great  principles.  The  Struggle  for  Life  vatd^ws, 
that  more  creatures  are  produced  than  there  is 
room  in  the  world  for.  Natural  Selection  (or  Sur- 
vival of  the  Fittest)  means  that  among  them  all 
those  which  happen  to  be  best  adapted  to  their 
particular  circumstances  oftenest  succeed  and 
leave  most  offspring. 

By  the  action  of  the  two  great  principles  in 
question  (which  affect  all  life,  animal  or  yegeta- 
ble)  the  world  has  been  gradually  filled  with  an 
immense  variety  of  wonderful  and  beautiful  crea- 
tures, all  ultimately  descended  (as  modern  thinkers 
hold)  from  the  selfsame  ancestors.  The  simple 
little  green  jelly-speck,  which  is  the  primitive 
plant,  has  given  rise  in  time  to  the  sea-weeds  and 
liverworts,  then  to  the  mosses  and  ferns,  then  to 
the  simplest  flowering  plants,  thence  to  the  shrubs 
and  trees,  and  finally  to  all  the  immense  wealth 
and  variety  of  fruits,  flowers,  and  foliage  we  now 
see  around  us. 

The  rest  of  this  book  will  consist  mainly  of  an 
exposition  of  the  results  brought  about  among 
plants  by  Variation,  the  Struggle  for  Life^  and 
Survival  of  the  Fittest.  But  before  we  go  on  to 
examine  them  in  detail,  I  shall  give  just  a  few 


30  THE   STORY   OF   THE   PLANTS. 

characteristic  instances  which  show  the  mode  of 
action  of  these  important  principles. 

There  is  a  pretty  wild  flower  in  our  hedges 
called  a  red  campion,  or  "  Robin  Hood."  Now, 
a  single  red  campion  produces  in  a  year  three 
thousand  seeds.  But  there  are  not  three  thou- 
sand times  as  many  red  campions  this  year  as 
last,  nor  will  there  be  three  thousand  times  as 
many  more  again  next  season.  Indeed,  if  an 
annual  plant  had  only  two  seeds,  each  of  which 
lived  and  produced  two  more,  and  so  on  contin- 
ually, in  twenty  years  its  descendants  would 
amount  to  no  less  than  a  million.  From  all  this 
it  necessarily  results  that  a  Struggle  for  Existence 
must  take  place  among  plants;  they  fight  wdth 
one  another  for  the  soil,  the  rain,  the  carbon,  the 
sunshine. 

Again,  take  such  a  wild  flower  as  this  very  red 
campion.  Why  has  it  light  pink  petals  ?  The 
reason  is,  to  attract  the  insects  which  fertilise  it. 
Flowers,  in  which  the  pollen  is  carried  by  the 
wind,  7iever  have  brilliant  or  conspicuous  blossoms  ; 
but  flowers  which  are  fertilised  by  insects  have 
almost  always  coloured  petals  to  tell  the  insects 
where  to  find  the  honey.  How  did  this  come 
about?  In  this  way,  I  imagine:  Many  plants 
produce  a  sweet  juice  on  their  leaves — for  exam- 
ple, the  common  laurel.  This  juice,  which  is 
probably  of  no  particular  use  to  them,  is  very 
greedily  eaten  by  insects.  Now  suppose  some 
flower,  by  accident  at  first,  happened  to  produce 
such  sweet  juice  near  its  stamens,  which  (as  we 
saw)  are  the  organs  for  making  pollen,  and  also 
near  its  pistil,  which  contains  its  young  seeds  or 
ovules.  Then  insects  would  naturally  visit  it  to 
eat  this    sweet    juice,  which    we    commonly    call 


HOW    PLANTS   CAME   TO    DIFFER.  31 

honey.  In  eating  it,  they  would  dust  themselves 
over  with  the  floury  pollen,  by  pure  accident,  and 
they  would  carry  some  of  it  away  with  them  on 
their  heads  and  legs  to  the  next  flower  they 
visited.  Chance  would  make  them  often  rub  off 
the  pollen  and  fertilise  the  flower ;  and  as  such 
cross-fertilisation,  as  it  is  called,  is  good  for  the 
plants,  producing  very  strong  and  vigorous  seed- 
lings, the  young  ones  so  set  would  have  the  best 
chance  of  flourishing  and  surviving  in  the  Struggle 
for  Existence.  Thus  the  flowers  which  made  most 
honey  would  be  oftenest  visited  and  crossed,  so 
that  they  would  soon  become  very  numerous. 
Again,  if  they  happened  to  have  bright  leaves 
near  the  honey,  they  would  be  most  readily  dis- 
criminated, and  oftenest  visited.  So,  in  the  long 
run,  it  has  come  about  that  almost  all  the  flowers 
fertilised  by  insects  produce  honey  to  allure  them, 
and  have  brilliant  petals  to  guide  their  allies  to 
the  honey.  That,  in  fact,  is  what  beautiful  flowers 
are  for — to  attract  the  fertilising  bees  and  butter- 
flies to  visit  and  impregnate  the  various  blossoms. 
Take  one  more  case — or,  rather,  the  same 
case,  extended  a  little  further.  The  red  cam- 
pion flowers  by  day,  and  is  fertilised  by  butter- 
flies ;  therefore  it  is  pink,  because  pink  is  an 
attractive  colour  in  the  daylight;  and  it  is  scent- 
less, because  its  colour  alone  is  quite  enough  to 
attract  sufficient  insects.  But  it  has  a  close  rela- 
tion, the  white  campion,  which  flowers  by  night 
only,  and  lays  itself  out  to  be  visited  by  moths  in 
the  twilight.  Why  is  this  kind  white  ?  Because 
no  other  colour  is  seen  so  well  in  the  dusk  ;  a  red 
or  pink  blossom  would  then  be  almost  invisible. 
Moreover,  the  white  campion  is  heavily  scented, 
as  are  almost  all  other  night-flowering  blossoms, 


32  THE   STORY   OF   THE   PLANTS. 

like  the  jasmine,  the  tuberose,  the  stephanotis, 
and  the  gardenia.  Observe  the  numerous  points 
of  similarity  :  all  these  are  white;  all  are  sweet- 
scented  ;  all  are  moth-fertilised.  Why  is  this  ? 
Because  the  scent  helps  to  show  the  moth  the  way 
to  the  flower  when  there  is  hardly  enough  light 
for  him  to  see  the  white  petals.  Thus  every  plant 
is  adapted  to  its  particular  station  in  life,  and  its 
adaptation  is  the  result  of  the  Struggle  for  Exist- 
ence, and  Survival  of  the  Fittest. 

Briefly  put,  whatever  variation  helps  the  plant 
in  any  way  in  any  particular  place,  or  at  any  par- 
ticular time,  is  likely  to  give  it  an  extra  chance  in 
the  fight,  and  is  therefore  reproduced  in  all  its 
descendants. 

So  that  is  how  plants  began  to  vary. 

To  sum  up.  Plants  grow,  because  they  keep 
on  continually  taking  in  carbon  and  hydrogen 
from  the  world  outside  them,  under  the  influence 
of  sunlight.  They  multiply,  because  when  they 
have  attained  a  certain  size  they  split  up  to  form 
two  or  more  individuals.  They  struggle  for  life 
with  one  another,  because  more  are  produced  than 
can  find  means  of  livelihood.  And  the  struggle 
results  in  Survival  of  the  Fittest. 

Or,  looked  at  in  another  light.  Plants  multi- 
ply, and  as  they  multiply  by  division  the  new  ones 
on  the  whole  resemble  their  parents;  this  is  the 
law  of  Heredity.  But  they  do  not  exactly  resem- 
ble them  in  every  detail ;  this  is  the  law  of  Vari- 
ation. And  as  some  variations  are  to  the  good, 
and  some  to  the  bad,  the  better  survive  and 
produce  young  like  themselves  oftener  than  the 
worse  do  ;  this  is  the  law  of  Natural  Selection. 


HOW   PLANTS   EAT.  33 

CHAPTER   IV. 

HOW    PLANTS    EAT. 

We  saw  in  the  last  chapter  how  and  why  plants 
came  to  differ  from  one  another,  but  not  why  they 
came  to  be  divided  into  well-marked  groups  or 
kinds,  such  as  primroses,  daisies,  cabbages,  oaks, 
and  willows.  In  the  world  around  us  we  observe 
a  great  many  different  sorts  of  plants,  not  all 
mixed  up  together,  so  to  speak,  nor  merging  into 
one  another  by  endless  gradations,  but  often 
clearly  marked  off  by  definite  lines  into  groups  or 
families.  Thus  a  primrose  is  quite  distinct  from 
a  crocus,  and  an  oak  from  a  maple.  For  the  pres- 
ent, however,  I  do  not  propose  to  go  into  the 
question  of  how  they  came  to  be  divided  into  such 
natural  groups.  1  will  begin  by  telling  you  briefly 
how  plants  eat  and  drink,  marry  and  rear  families, 
and  then  will  return  later  on  to  this  problem  of 
the  Origin  of  Species^  as  it  is  called,  and  the 
pedigrees  and  relationships  of  the  leading  plant 
families. 

First  of  all,  then,  we  will  inquire,  How  Fla?iis 
Eat.  And  in  this  inquiry  I  will  neglect  for  the 
most  part  the  very  early  and  simple  plants  we 
have  already  spoken  about,  and  will  chiefly  deal 
with  those  more  advanced  and  complicated  types, 
the  flowering  plants,  with  which  everybody  is  fa- 
miliar. 

Plants  Eat  with  their  Leaves.  The  leaves  are, 
in  fact,  their  mouths  and  stomachs. 

Now,  what  is  a  leaf  ?  It  is  usually  a  rather 
thin,  flat  body,  often  with  two  parts,  a  stalk  and 

3 


34        THE  STORY  OF  THE  PLANTS. 

a  blade,  as  in  the  oak  or  the  beech ;  though  some- 
times the  stalk  is  suppressed,  as  in  grass  and  the 
teasel.  Almost  always,  however,  the  leaf  is  green  : 
it  is  broad  and  flat,  with  a  large  expanded  surface, 
and  this  surface  is  spread  out  horizontally,  so  as 
to  catch  as  much  as  possible  of  the  sunlight  that 
falls  upon  it.  Its  business  is  to  swallow  carbonic 
acid  from  the  air,  and  digest  and  assimilate  it  un- 
der the  influence  of  sunlight.  And  as  different 
situations  require  different  treatment,  various 
plants  have  leaves  of  very  different  shapes,  each 
adapted  to  the  habits  and  manners  of  the  particu- 
lar kind  that  produces  them.  The  difference  has 
been  brought  about  by  Natural  Selection. 

^/z(3;/ does  the  leaf  eat  ?  Carbonic  acid.  There 
is  a  small  quantity  of  this  gas  always  floating  about 
dispersed  in  the  air,  and  plants  fight  with  one  an- 
other to  get  as  much  as  possible  of  it.  Most  peo- 
ple imagine  plants  grow  out  of  the  soil.  This  is 
quite  a  mistake.  The  portion  of  its  solid  material 
which  a  plant  gets  out  of  the  soil  (though  abso- 
lutely necessary  to  it)  is  hardly  worth  taking  into 
consideration,  numerically  speaking;  by  far  the 
larger  part  of  its  substance  comes  directly  out  of 
the  air  as  carbon,  or  out  of  the  water  as  hydrogen 
and  oxygen.  You  can  easily  see  that  this  is  so  if 
you  dry  a  small  bush  thoroughly,  leaves  and  all, 
and  then  burn  it.  What  becomes  of  it  in  such 
circumstances  ?  You  will  find  that  the  greater 
part  of  it  disappears,  or  goes  off  into  the  atmos- 
phere ;  the  carbon,  uniting  with  oxygen,  goes  off 
in  the  form  of  carbonic  acid,  while  the  hydrogen, 
uniting  with  oxygen,  goes  off  in  the  form  of  steam 
or  vapour  of  water.  What  is  there  left  ?  A  very 
small  quantity  of  solid  matter,  which  we  know  as 
ash.     Well,  that  ash,  which  returns  to  the  soil  in 


HOW   PLANTS   EAT.  35 

the  solid  condition,  is  practically  almost  the  only 
part  the  plant  got  from  the  soil ;  the  rest  returns 
as  gas  and  vapour  to  the  air  and  water,  from 
which  the  plant  took  them.  You  must  never  for- 
get this  .most  important  fact,  that  plants  grow 
mainly  from  air  and  ivater,  and  hardly  at  all  from 
the  soil  beneath  them.  Unless  you  keep  it  firmly 
in  mind,  you  will  not  understand  a  great  deal  that 
follows. 

Why,  then,  do  gardeners  and  farmers  think  so 
much  about  the  soil  and  so  little  about  the  air, 
which  is  the  chief  source  of  all  living  material  ? 
We  shall  answer  that  question  in  the  next  chapter, 
when  we  come  to  consider  What  Plants  Drink,  and 
what  food  they  take  up  dissolved  in  their  water. 

Carbonic  acid,  though  itself  a  gas,  is  the  chief 
source  of  the  solid  material  of  plants.  How  do 
plants  eat  it  ?  By  means  of  the  green  leaves,  which 
suck  in  floating  particles  of  the  gaseous  food. 
Their  eating  is  thus  more  like  breathing  than 
ours :  nevertheless,  it  is  true  feeding :  it  is  their 
way  of  taking  in  fresh  material  for  building  up 
their  bodies.  If  you  examine  a  thin  slice  from  a 
leaf  under  the  microscope,  you  will  find  that  its 
upper  surface  consists  of  a  layer  of  cells  with 
transparent  walls,  and  no  colouring  matter  (Fig. 
i).  These  cells  are  full  of  water  ;  they  form  a 
sort  of  water-cushion  on  the  top  of  the  leaf,  which 
drinks  in  carbonic  acid  (or,  to  be  quite  correct,  its 
floating  form,  carbon  dioxide)  from  the  air  about 
it.  Immediately  below  this  cushion  of  water-cells 
you  come  again  upon  a  firm  layer  of  closely-packed 
green  cells,  filled  with  living  green-stuff,  which  take 
the  carbonic  acid  in  turn  from  the  water-cells,  and 
manufacture  it  forthwith  into  sugars,  starches,  and 


36        THE  STORY  OF  THE  PLANTS. 

Other  materials  of  living  bodies.  The  lowest 
spongy  part  evaporates  unnecessary  water,  and 
so  helps  to  keep  up  circulation. 

The  plant  has  often  many  hundred  leaves,  that 
is  to  say,  many  hundred  mouths  and  stomachs. 
Why  do  plants  need  so  many  when  we  have  but 


^oaogaooooocDQ 


Fig.  I. — A  thin  slice  from  a  leaf,  seen  under  the  microscope.  On 
top  are  water-cells,  which  suck  in  carbonic  acid.  Beneath  these 
are  green  cells,  which  assimilate  ^t  under  the  influence  of  sun- 
light.    The  spongy  lower  portion  is  used  for  evaporation. 

one  ?  Because  they  cannot  move,  and  because 
their  food  is  a  gas,  diffused  in  minute  quantities 
through  all  the  atmosphere.  They  have  to  suck 
it  in  wherever  they  can  find  it.  And  what  do 
they  do  with  the  carbonic  acid  when  once  they 
have  got  it  ?  Well,  to  answer  that  question,  I 
must  tell  you  a  little  more  about  what  the  ordi- 
nary green  leaf  is  made  of,  and  especially  about 
the  green-stuff  in  its  central  cells. 

Now  what  is  this  green-stuff  ?  It  is  the  true 
life-material  of  the  plant,  the  origin  of  all  the 
living  matter  in  nature.    You  and  I.  as  well  as  the 


HOW   PLANTS   EAT.  37 

plants  themselves,  are  entirely  built  up  of  living 
jelly  which  this  green-stuff  has  manufactured 
under  the  influence  of  sunlight.  And  the  mate- 
rial that  does  this  is  such  an  important  thing  in 
the  history  of  life  that  I  will  venture  to  trouble 
you  with  its  scientific  name,  Chlorophyll. 
When  sunlight  falls  upon  the  Chlorophyll  or 
green-stuff  in  a  living  leaf,  in  the  presence  of 
carbonic  acid  and  water,  the  chlorophyll  (or,  to  be 
quite  accurate,  the  living  matter  or  protoplasm 
with  chlorophyll  embedded  in  it)  at  once  proceeds 
to  set  free  the  oxygen  (which  it  turns  loose  upon 
the  air  again),  and  to  build  up  the  carbon  and  hy- 
drogen (with  a  little  oxygen)  by  various  stages 
into  a  material  called  starch.  This  starch,  as  you 
know,  possesses  energy — that  is  to  say,  latent  light 
and  dormant  heat  and  movement,  because  we  can 
eat  it  and  burn  it  within  our  bodies.  Other  mate- 
rials, hydro-carbons  and  carbo-hydrates,  as  they 
are  called,  are  made  in  the  same  way.  The  main 
use  of  leaves,  then,  is  to  eat  carbon  and  drink 
water,  and,  under  the  influence  of  sunlight,  to  take 
in  energy  and  build  them  up  into  living  material. 
The  starch  and  sugar  and  other  things  thus 
made  are  afterwards  dissolved  in  the  sap,  and 
used  by  the  plant  to  manufacture  new  cells  and 
leaves,  or  to  combine  with  other  important  mate- 
rials of  which  I  shall  speak  hereafter,  in  order  to 
form  fresh  protoplasm  with  chlorophyll  in  it. 

Now  we  know  what  leaves  are  for;  and  you 
can  easily  see,  therefore,  that  they  are  by  far 
the  most  essential  and  important  part  of  the 
entire  plant.  Most  plants,  in  fact,  consist  of 
little  else  than  colonies  of  leaves,  together  with 
the  flowers  which  are  their  reproductive  or- 
gans.    We  have  next  to  see  What  Shapes  various 


38        THE  STORY  OF  THE  PLANTS. 

Leaves  assume^  and  what  are  their  reasons  for  do- 
ing so. 

The  leaf  has,  as  a  rule,  to  be  broad  and  flat, 
in  order  to  catch  as  much  carbon  as  possible ;  it 
has  also  usually  to-be  expanded  horizontally  to 
the  sunlight,  so  as  to  catch  and  fix  it.  For  this 
reason,  most  leaves  that  can  raise  themselves 
freely  to  the  sun  and  air  are  flat  and  horizontal. 
But  in  very  crowded  and  overgrown  spots,  like 
thickets  and  hedgerows,  the  leaves  have  to  fight 
hard  with  one  another  for  air  and  sunlight ;  and 
in  such  places  particular  kinds  of  plants  have 
been  developed,  with  leaves  of  special  forms 
adapted  to  the  situation.  The  fittest  have  sur- 
vived, and  have  assumed  such  shapes  as  natural 
selection  dictated. 

Where  the  plants  are  large  and  grow  freely 
upward,  with  plenty  of  room,  the  leaves  are  usu- 
ally broad  and  expanded,  as  in  the  tobacco-plant 
and  the  sunflower.  Where  the  plants  grow  thick 
and  close  in  meadows,  the  leaves  are  mostly  long 
and  narrow,  like  grasses.  In  overgrown  clumps 
and  hedgerows  they  are  generally  much  subdi- 
vided into  numerous  little  leaflets,  as  is  the  case 
with  most  ferns,  and  also  with  herb-Robert,  chervil, 
milfoil,  and  vetches.  In  these  last  cases,  the  plant 
wants  to  get  as  much  of  the  floating  carbonic 
acid,  and  of  the  sunlight,  as  it  can  ;  and  therefore 
it  makes  its  leaves  into  a  sort  of  divided  network, 
so  as  to  entrap  the  smallest  passing  atom  of  car- 
bon, and  to  intercept  such  stray  rays  of  broken 
sunlight  as  have  not  been  caught  by  the  taller 
plants  above  it.  In  almost  all  cases,  too,  the 
leaves  on  the  same  plant  are  so  arranged  round 
the  stem  and  on  the  branches  as  to  interfere  with 
one  another  as  little  as  possible;  they  are  placed 


HOW   PLANTS   EAT.  39 

in  an  order  which  allows  the  sunshine  to  reach 
every  leaf,  and  which  secures  a  free  passage  of 
air  between  them. 

An  interesting  example  of  the  way  some  of 
these  principles  work  out  in  practice  is  afforded 
us  by  a  common  little  English  pond-weed,  the 
water-crowfoot.  This  curious  plant  grows  in 
streams  and  lakes,  and  has  two  quite  different 
types  of  leaves,  one  floating,  and  one  submerged. 
The  floating  leaves  have  plenty  of  room  to  de- 
velop themselves  freely  on  the  surface  of  the 
pond  ;  they  loll  on  the  top,  well  supported  by  the 
mass,  of  water  beneath;  and,  as  there  is  little 
competition,  they  can  get  an  almost  unlimited 
supply  of  carbonic  acid  and  sunshine.  There- 
fore, they  are  large  and  roundish,  like  a  very  full 
ivy-leaf.  But  the  submerged  leaves  wave  up  and 
down  in  the  water  below,  and  have  to  catch  what 
little  dissolved  carbonic  acid  they  can  find  in  the 
pond  around  them.  Therefore  they  are  dissected 
into  endless  hair-like  ends,  which  move  freely 
about  in  the  moving  water  in  search  of  food- 
stuff. The  two  types  may  be  aptly  compared  to 
lungs  and  gills,  only  in  the  one  case  it  is  car- 
bonic acid  and  in  the  other  case  oxygen,  that 
the  highly-dissected  organs  are  seeking  in  the 
water. 

As  a  general  rule,  when  a  plant  can  spread  its 
leaves  freely  about  through  unoccupied  air,  with 
plenty  of  sunlight,  it  makes  them  circular,  or 
nearly  so,  and  supports  them  by  means  of  a  stem 
in  the  middle.  This  is  particularly  the  case  with 
floating  river-plants,  such  as  the  water-lily  and 
the  water-gentian.  But  even  terrestrial  plants, 
when  they  can  raise  their  foliage  easily  into 
unoccupied  space,  free    from    competition,  have 


40        THE  STORY  OF  THE  PLANTS. 

similar  round  leaves,  supported  by  a  central  leaf- 
stalk, as  is  the  case  with  the  familiar  garden 
annual  popularly  (though  erroneously)  known  as 
nasturtium.  (Its  real  name  is  Tropaeolum.)  On 
the  other  hand,  when  a  plant  has  to  struggle 
hard  for  carbon  and  sunlight  in  overgrown 
thickets,  or  under  the  water,  it  has  usually  very 
much  subdivided  leaves,  minutely  cut,  again  and 
again,  into  endless  segments.  Submerged  leaves 
invariably  display  this  tendency. 

But  that  does  not  conclude  the  whole  set  of 
circumstances  which  govern  the  forms  and  size 
of  leaves.  Not  only  do  they  want  to  eat,  and  to 
have  access  to  sunshine  ;  they  must  also  be  sup- 
ported or  held  in  place  so  as  to  catch  it.  For 
this  purpose  they  have  need  of  what  we  may 
venture  to  describe  as  foliar  architecture.  This 
architecture  takes  the  form  of  ribs  or  beams  of 
harder  material,  which  ramify  through  and  raise 
aloft  the  softer  and  actively  living  cell-stuff. 
They  are,  as  it  were,  the  skeleton  or  framework 
of  the  leaf;  and  in  what  are  commonly  known 
as  "  skeleton  leaves  "  the  living  cell-stuff  between 
has  been  rotted  away,  so  as  to  display  this  harder 
underlying  skeleton  or  framework.  It  is  com- 
posed of  specially  hardened,  lengthened,  and 
strengthened  cells,  and  is  intended,  not  only  to 
do  certain  living  work  in  the  plant  (as  we  shall 
see  hereafter),  but  also  to  form  a  supporting 
scaffolding.  The  material  of  which  ribs  or  beams 
are  composed  is  called  "  vascular  tissue  " — a  not 
very  well  chosen  name,  as  this  material  has  only 
a  slight  analogy  to  what  is  called  the  vascular 
system  (or  network  of  blood-vessels)  in  an  animal 
body.     It  is  much  more  like  the  bony  skeleton. 


HOW   PLANTS   EAT. 


41 


Similarly,  the  ribs  themselves  are  usually  called 
veins — a  very  bad  name  again,  as  they  are  much 
more  like  the  bones  of  a  wing  or  hand ;  they  are 
mainly  there  for  support,  as  a  bony  or  wooden 
framework,  though  they  also  act  for  the  convey- 
ance of  sap  or  water. 

And  now  we  are  in  a  position  to  begin  to 
understand  the  various  shapes  of  leaves  as  we 
see  them  in  nature.  They  depend  most  of  all 
upon  certain  inherited  types  of  ribs  or  so-called 
veins,  and  these  types  are  usually  pretty  constant 
in  great  groups  of  plants  closely  related  by  de- 
scent to  one  another.  The  immense  difference  in 
their  external  shape  (which  often  varies  enor- 
mously even  on  the  same  stem)  is  mainly  due  to 
the  relative  extent  to  which  the  framework  is 
filled  out  or  not  with  living  cell-stuff,  or,  as  it  is 
technically  called,  cellular  tissue. 

There  are  two  chief  ways  of  arranging  the  ribs 
or  veins  in  a  leaf,  which  may  be  distinguished  as 


Fig.  2. — Finger-veined  leaves.    The  veins  are  the  same  in  the  three 
leaves,  but  they  differ  in  the  amount  to  which  they  are  filled  in. 


\.\\Q  finger-like  and  th.^  feather-like  methods  (in  tech- 
nical language, /(^//;/^?/t'  ^.nd  pin?iafe).  In  the  ^;/- 
ger-like  plan  the  ribs  all  diverge  from  a  common 
point,  more  or   less  radially.     In  the  feather-like 


42 


THE   STORY   OF  THE   PLANTS. 


plan  the  ribs  are  arranged  in  opposite  pairs  along 
the  sides  of  a  common  line  or  midrib.  Yet  even 
these  two  distinct  plans  merge  into  one  another 
by  imperceptible  degrees,  as  you  can  see  if  you 
look  at  the  accompanying  diagram. 

Now  let  us  take  first  the  finger-veined  type 
(Fig.  2).  Here,  if  all  the  interstices  of  the  ribs 
are  fully  filled  out  with  cellular  tissue,  w^e  get  a 
roundish  leaf  like  that  of  the  so-called  nastur- 
tium. But  if  the  ribs  project  a  little  at  the  edge 
— in  other  words,  if  the  cellular  tissue  does  not 


W 


Fig.    3. — Feather- veined    leaves.      The    four   leaves   have   similar 
veins,  but  are  differently  filled  in. 


quite  fill  out  the  whole  space  between  them — we 
get  a  slightly  indented  leaf,  like  that  of  the  scar- 
let geranium  or  the  common  mallow.  If  the  un- 
filled spaces  between  the  ends  of  the  ribs  are 
much  greater,  then  the  ribs  project  into  marked 
points  or  lobes,  and  we  get  a  leaf  like  that  of  ivy. 
Carry  the  starving  of  the  cellular  tissue  a  little 
further  still,  and  we  have  a  deeply-indented  leaf 
like  that  of  the  castor-oil  plant.  Finally,  let  the 
spaces  unfilled  go  right  down  to  the  common 
centre  from  which  the  ribs  radiate,  and  we  get  a 


HOW   PLANTS   EAT. 


43 


divided  or  compound  leaf,  like  that  of  the  horse- 
chestnut,  with  three,  five,  or  seven  separate  leaf- 
lets.    (See  Fig.  5,  No.  i.) 

Similarly  with  the  feather-veined  type  (Fig.  3) ; 
the  spaces  between  the  ribs  may  be  more  or  less 


Fig.  4. — Two  leaves.     I,  finger-veined,  but  lobed,  like  scarlet  gera- 
nium ;  II,  feather- veined,  but  lobed,  like  oak. 


Fig.  5. — Two  leaves.  I,  finger-veined,  but  divided  into  separate 
leaflets,  like  horse-chestnut ;  II,  feather-veined,  but  divided  into 
separate  leaflets,  like  vetch. 


filled  with  cellular  tissue  in  any  degree  you  choose 
to  mention.  When  they  are  very  fully  filled  out, 
you  get  a  leaf  like  that  of  bladder  senna.  A  little 
more  pointed,  and  less  filled  out  at  the  tips,  it  be- 


44        THE  STORY  OF  THE  PLANTS. 

comes  like  argel.  When  the  edge  is  not  quite 
filled  out,  but  irregularly  indented,  we  get  forms 
like  the  oak  leaf.  Finally,  when  the  indentations 
go  to  the  very  bottom  of  each  vein,  so  as  to  reach 
the  midrib,  we  get  a  compound  leaf  like  that  of 
the  vetch,  with  a  number  of  opposite  and  distinct 
leaflets. 

The  reason  why  some  leaves  are  thus  more 
filled  out  than  others  is  simply  this  :  it  depends 
upon  the  freedom  of  their  access  to  air  and  sun- 
light. I  do  not  mean  the  freedom  of  access  of 
the  particular  leaf  or  the  particular  plant,  but  the 
average  ancestral  freedom  of  access  in  the  kind 
they  belong  to.  Each  kind  has  adapted  itself,  as 
a  rule,  to  certain  situations  for  which  it  has  spe- 
cial advantages,  and  it  has  learnt  by  the  teaching 
of  natural  selection  to  produce  such  leaves  as  best 
fit  its  chosen  site  and  habits.  Where  access  to 
carbon  and  sunlight  are  easy,  plants  usually  pro- 
duce very  full  round  leaves,  with  alT  the  inter- 
stices between  the  ribs  filled  amply  in  with  cellular 
tissue  ;  but  where  access  is  difficult,  they  usually 
produce  rather  starved  and  unfilled  leaves,  which 
consist,  as  it  were,  of  scarcely  covered  skeletons 
(Figs.  4  and  5).  This  last  condition  is  particu- 
larly observable  in  submerged  leaves,  and  in  those 
which  grow  in  very  crowded  situations. 

The  two  types  of  rib-arrangement  to  which  I 
have  already  called  attention  exist  for  the  most 
part  in  one  of  the  two  great  groups  of  flowering 
plants  about  which  I  shall  have  more  to  say  to 
you  hereafter.  There  is  yet  a  third  type,  how- 
ever, which  occurs  in  the  other  great  group  (that 
of  the  grasses  and  lilies),  and  it  is  known  as  the 
parallel  (Fig.  6).  In  this  type,  the  ribs  do  not 
form  a  radiating  network  at  all,  but  run  straight, 


HOW   PLANTS   EAT. 


45 


or  nearly  so,  through  the  leaves.  Examples  of  it 
occur  in  almost  all  grasses,  and  in  tulips,  daffo- 
dils, lily  of  the  valley,  and  narcissus.  Leaves  of 
this  sort  have  seldom  any  leaf-stalk ;  they  usually 
rise  straight  out  of  the  ground,  more  or  less  erect, 
and  their  architectural  plan  is  generally  quite 
simple.  They  are  seldom 
toothed,  and  hardly  ever 
divided  into  deeply  -  cut 
segments  or  separate  leaf- 
lets. 

A  few  more  peculiari- 
ties in  the  shapes  of  leaves 
must  still  be  noted,  and 
a  few  words  used  in  de- 
scribing them  must  be  ex- 
plained very  briefly.  When 
the  leaf  consists  all  of  one 
piece,  no  matter  how  much 
cut  up  and  indented  at  the 
edge,  it  is  said  to  be  "  simple 
into  distinct   leaflets  (as  in 

"  compound."  If  the  edge  is  unindented  all  round 
(as  in  Fig.  6),  we  say  the  leaf  is  "  entire" ;  if  the 
ribs  form  small  projections  at  the  edge  (as  in 
Fig.  4),  we  call  it  "  toothed  " ;  if  the  divisions  are 
deeper,  we  say  it  is  "  lobed  "  ;  and  when  the  lobes 
are  very  deeply  cut  indeed,  we  call  it  "  dissected." 
Thus,  in  order  to  describe  accurately  the  shape 
of  a  leaf,  we  need  only  say  which  way  it  is  veined 
or  ribbed — whether  finger-wise,  feather-wise,  or 
with  parallel  veins — and  how  much,  if  at  all,  it  is 
cut  or  divided. 

Endless  varieties,  however,  occur,  in  accord- 
ance with  the  peculiar  place  the  plant  and  its 
kind  have  been  developed  to  inhabit.     In  climb- 


II 

Fig.  6. — I,  parallel  veins,  as 
seen  in  one  great  group 
of  plants,  the  lilies ;  II, 
branching  veins,  as  seen  in 
another  great  group,  the 
trees  and  herbs  of  the 
usual  type. 

" ;  but  if  it  is  divided 
Fig.  5),  it  is  called 


46  THE   STORY   OF   THE   PLANTS. 

ing  plants,  for  example,  the  leaves  are  usually 
opposite,  so  as  to  clutch  more  readily,  and  they 
are  almost  always  more  or  less  heart-shaped  at 
the  base,  as  in  convolvulus  and  black  briony. 
The  leaves  of  forest  trees,  on  the  other  hand, 
tend  to  be  what  is  known  as  ovate  in  shape,  like 
the  beech  and  the  poplar  ;  while  those  of  the 
lime  are  a  little  one-sided,  in  order  that  each  leaf 
may  not  overshadow  and  rob  its  neighbour.  This 
one-sidedness  is  even  more  markedly  seen  in  the 
hot-house  begonias.  Some  leaves,  again,  are  mi- 
nutely subdivided  into  leaflets  twice  or  three 
times  over  ;  such  leaves  are  said  to  be  doubly  or 
trebly  compound.  But  if  you  study  plants  as 
they  grow  (and  this  book  is  written  in  the  hope 
that  it  may  induce  you  to  do  so),  you  will  gener- 
ally be  able  to  see  that  the  shapes  and  peculiari- 
ties of  leaves  have  some  obvious  reference  to 
their  place  in  the  w^orld,  and  their  habits  and 
manners. 

I  have  spoken  so  far  mainly  of  quite  central 
and  typical  leaves,  which  are  arranged  with  a 
single  view  to  the  need  for  feeding.  But  plants 
are  exposed  to  many  dangers  in  life  besides  the 
danger  of  starvation,  and  they  guard  in  various 
ways  against  all  these  dangers.  One  very  ob- 
vious one  is  the  danger  of  being  devoured  by 
grazing  animals,  and,  to  protect  themselves 
against  it,  many  plants  produce  leaves  which  are 
prickly,  or  stinging,  or  otherwise  unpleasant. 
The  common  holly  is  a  familiar  instance.  In 
this  case  the  ribs  are  prolonged  into  stiff  and 
prickly  points,  which  wound  the  tender  noses  of 
donkeys  or  cattle.  We  can  easily  see  how  such  a 
protection   could  be  acquired  by  the  holly-bush 


HOW   PLANTS   EAT.  ^  47 

through  the  action  of  Variation  and  Natural  Se- 
lection. For  holly  grows  chiefly  in  rough  and 
wild  spots,  where  all  the  green  leaves  are  liable 
to  be  eaten  by  herbivorous  animals.  If,  there- 
fore, any  plant  showed  the  slightest  tendency 
towards  prickliness  or  thorniness,  it  would  be 
more  likely  to  survive  than  its  unprotected  neigh- 
bours. And  indeed,  as  a  matter  of  fact,  you  will 
soon  see  that  almost  all  the  bushes  and  shrubs 
which  frequent  commons,  such  as  gorse,  butcher's 
broom,  hawthorn,  blackthorn,  and  heather,  are 
more  or  less  spiny,  though  in  most  of  these  cases 
it  is  the  branches,  not  the  leaves,  that  form  the 
defensive  element.  Holly,  however,  wastes  no 
unnecessary  material  on  defensive  spikes,  for 
though  the  lower  leaves,  within  reach  of  the  cat- 
tle and  donkeys,  are  very  prickly  indeed,  you  will 
find,  if  you  look,  that  the  upper  ones,  above  six 
or  eight  feet  from  the  ground,  are  smooth-edged 
and  harmless.  These  upper  leaves  stand  in  no 
practical  danger  of  being  eaten,  and  the  holly 
therefore  takes  care  to  throw  away  no  valuable 
material  in  protecting  them  from  a  wholly  imagi- 
nary assailant. 

Often,  too,  in  these  prickly  plants  we  can 
trace  some  memorial  of  their  earlier  history. 
Gorse,  for  example,  is  a  peaflower  by  family,  a 
member  of  the  great  group  of  "papilionaceous," 
or  butterfly-blossomed,  plants,  which  includes  the 
pea,  the  bean,  the  laburnum,  the  clover,  and  many 
other  familiar  trees,  shrubs,  and  climbers.  It  is 
descended  more  immediately  from  a  special  set 
of  trefoil-leaved  peaflowers,  like  the  clovers  and 
lucernes ;  but  owing  to  its  chosen  home  on  open 
uplands,  almost  all  its  upper  leaves  have  been 
transformed   for  purposes  of  defence  into  sharp, 


48  THE   STORY   OF  THE   PLANTS. 

spine-like  prickles.  Indeed,  the  leaves  and 
branches  are  both  prickly  together,  so  that  it  is 
difficult  at  first  sight  to  discriminate  between 
them.  But  if  you  take  a  seedling  gorse  plant  you 
will  find  that  in  its  early  stages  it  still  produces 
trefoil  leaves,  like  its  clover-like  ancestors;  and 
these  leaves  are  almost  exactly  similar  to  those 
of  the  common  genista  so  much  cultivated  in 
hot-houses.  As  the  plant  grows,  however,  the 
trefoil  leaves  gradually  give  place  to  long  and 
narrow  blades,  and  these  in  turn  to  prickly  spines, 
like  the  adult  gorse-leaves  Hence  we  are  justi- 
fied in  believing  that  the  ancestors  of  gorse  were 
once  genistas,  bearing  trefoil  leaves;  and  that 
later,  through  the  action  of  natural  selection,  the 
prickliest  among  them  survived,  till  they  acquired 
their  existing  spiny  foliage.  In  every  case,  in- 
deed, yoimg  plants  tend  to  resemble  their  earlier  an- 
cestors, and  only  as  they  grow  up  acquire  their 
later  and  more  special  characteristics. 

And  now  I  must  add  one  word  about  the  ori- 
gin of  leaves  in  general.  Very  simple  plants,  we 
saw,  consist  of  a  single  cell,  which  is  not  merely 
a  leaf,  but  also  at  the  same  time  a  flower,  a  seed, 
a  root,  a  branch,  and  everything.  In  other  words, 
in  very  simple  plants  a  single  cell  does  rather 
badly  everything  which  in  more  advanced  and 
developed  plants  is  better  done  by  distinct  and 
highly-adapted  organs.  The  whole  evolution  of 
plants  consists,  in  fact,  in  the  telling  off  of  par- 
ticular parts  to  do  better  what  the  primitive  cell 
did  for  itself  but  badly.  Above  the  very  simple 
plants  which  consist  of  a  single  cell  come  other 
plants,  which  consist  of  many  cells  placed  end  on 
end  together,  as  in  the  case  of  the  hair-like  water- 


HOW   PLANTS   EAT.  49 

weeds;  and  above  these  again  come  other  and 
rather  higher  plants,  in  which  the  cellular  tissue 
assumes  the  form  of  a  flat  and  leaf-like  blade,  as 
in  many  broad  sea-weeds.  None  of  these,  how- 
ever, are  called  leaves  in  the  strict  sense,  because 
they  consist  of  cells  alone,  without  any  ribs  or 
supporting  framework.  The  higher  types,  how- 
ever, like  ferns  and  flowering  plants,  have  such 
ribs  or  frameworks,  made  of  that  stiffer  and 
tougher  material  called  vascular  tissue.  This  is 
the  most  general  distinction  that  exists  between 
plants;  the  higher  ones  are  known  as  Vascular 
Plants,  including  all  those  with  true  leaves,  such 
as  the  common  trees,  herbs,  and  shrubs,  and  the 
ferns  and  grasses — in  fact,  almost  all  the  things 
ever  thought  of  as  plants  by  most  ordinary  ob- 
servers; the  lower  ones  are  known  as  Cellular 
Plants,  and  include  the  kinds  without  true  leaves 
or  vascular  tissue,  such  as  the  seaweeds,  fungi, 
and  microscopic  plants  only  recognised  as  a  rule 
by  botanical  students. 

The  higher  plants,  then,  have  for  the  most 
part  special  organs,  the  leaves,  told  off  to  do 
work  for  them  as  mouths  and  stomachs;  while 
other  organs  are  told  off  to  do  other  special  work 
of  their  own — as  the  roots  to  drink,  the  flowers  to 
reproduce,  the  fruit  and  seeds  to  carry  on  the  life 
of  the  species  to  other  generations,  and  so  forth, 
down  to  the  hairs  that  protect  the  surface,  or  the 
glands  that  produce  honey  to  attract  the  fertilis- 
ing insects.  To  the  end,  however,  all  parts  of  the 
plant  retain  the  power  to  eat  carbonic  acid,  if 
necessary ;  so  that  many  higher  plants  have  no 
true  leaves,  but  use.  portions  of  .the  stem  or 
branches  for  the  purpose  of  feeding.  Any  part 
of  the  plant  which  contains  the  active  living 
4 


50        THE  STORY  OF  THE  PLANTS. 

green-stuff,  or  chlorophyll,  can  perform  the  func- 
tions of  a  leaf.  In  very  dry  or  desert  places, 
leaves  would  be  useless,  because  their  flat  and 
exposed  blades  would  allow  the  water  within  to 
evaporate  too  readily.  Hence  most  desert  plants, 
like  the  cactuses,  and  many  kinds  of  acacias  and 
euphorbias,  have  no  true  leaves  at  all ;  in  their 
place  they  have  thick  and  fleshy  stems,  often  very 
leaf-like  in  shape,  and  curiously  jointed.  These 
stems  are  covered  with  a  thick,  transparent  skin 
or  epidermis,  to  resist  evaporation,  and  are  pro- 
tected by  numerous  stinging  hairs  or  spines, 
which  serve  to  keep  off  the  attacks  of  animals. 
Stems  of  this  type  are  used  as  reservoirs  of  water, 
which  the  plant  sucks  up  during  the  infrequent 
rains  ;  and  as  they  contain  chlorophyll,  like  leaves, 
they  serve  in  just  the  same  way  as  swallowersand 
digesters  of  carbonic  acid. 

Many  other  plants  which  live  in.  dry  or  sandy 
places,  like  our  common  English  stone-crops,  do 
not  go  quite  as  far  as  the  cactuses,  but  have  thick 
and  fleshy  leaves  on  thick  and  fleshy  stems,  to 
prevent  evaporation.  As  a  general  rule,  indeed, 
the  drier  the  situation  a  plant  habitually  frequents 
the  fleshier  are  its  leaves,  and  the  greater  its  tend- 
ency to  make  the  stem  share  in  the  work  of  feed- 
ing, or  even  to  get  rid  of  foliage  altogether.  In 
Australia,  however,  most  of  the  forest  trees,  like 
the  eucalyptuses,  have  got  over  the  same  difficulty 
in  a  different  way ;  they  arrange  their  leaves  on 
the  stem  so  as  to  stand  vertically  to  the  sun's 
rays,  instead  of  horizontally,  which  saves  evapo- 
ration, and  makes  the  woodland  almost  entirely 
shadeless.  Many  of  these  Australian  trees,  how- 
ever, have  no  true  leaves,  but  use  in  their  place 
flattened  green  branches. 


HOW   PLANTS   EAT.  5  I 

Some  plants  are  annuals,  and  some  perennials. 
When  annuals  have  flowered  and  set  their  seed 
they  wither  and  die.  But  perennials  go  on  for 
several  seasons.  Most  of  them,  however,  in  cold 
climates  at  least,  shed  their  leaves  on  the  approach 
of  winter.  But  they  do  not  lose  all  the  valuable 
material  stored  up  in  them.  Trees  and  shrubs 
withdraw  the  starchy  matter  into  a  special  layer 
of  the  bark,  where  it  remains  safe  from  the  winter 
frosts,  and  is  used  up  again  in  spring  in  forming 
the  new  foliage.  This  new  foliage  is  usually  pro- 
vided for  in  the  preceding  season.  If  you  look 
at  a  tree  in  late  autumn,  after  the  leaves  have 
fallen,  you  will  see  that  it  is  covered  by  little 
knobs  which  we  know  as  buds.  These  buds  are 
the  foliage  of  the  coming  season.  The  outer  part 
consists  of  several  layers  of  dry  brown  scales, 
which  serve  as  an  overcoat  to  protect  the  tender 
young  leaves  within  from  the  chilly  weather. 
But  the  inner  layers  consist  of  the  delicate  young 
leaves  themselves,  which  are  destined  to  sprout 
and  grow  as  soon  as  spring  comes  round  again. 
Even  the  scales,  indeed,  are  very  small  leaves, 
with  no  living  material  in  them;  they  are  sacri- 
ficed by  the  plant,  as  it  were,  in  order  to  keep 
the  truer  leaves  within  snug  and  warm  for  the 
winter.  Nor  do  the  autumn  leaves  fall  off  by 
pure  accident ;  some  time  before  they  drop  the 
tree  arranges  for  their  fall  by  making  a  special 
row  of  empty  cells  where  the  leaf-stalk  joins  the 
stem  or  branch  ;  and  when  frost  comes  on,  the 
leaf  separates  quietly  and  naturally  at  that  point 
as  soon  as  the  valuable  starchy  and  living  mate- 
rial has  been  withdrawn  and  stored  in  the  perma- 
nent layers  of  the  bark  for  future  service. 

Smaller   and    more    succulent   plants   do   not 


52  THE   STORY  OF  THE   PLANTS. 

thus  withdraw  their  living  material  into  the  bark 
in  autumn  ;  but  they  attain  much  the  same  end  in 
different  manners.  Thus  lilies  and  onions  store 
the  surplus  material  they  lay  by  during  the  sum- 
mer at  the  base  of  their  long  leaves,  and  the 
swollen  bases  thus  formed  produce  what  we  call 
a  bulb,  which  carries  on  the  life  of  the  plant  to 
the  next  season.  Other  plants,  like  the  common 
English  orchids,  store  material  in  underground 
tubers;  while  others,  again,  and  by  far  the  great- 
er number,  so  store  it  in  the  root,  which  is  some- 
times thick  and  swollen,  or  in  an  underground 
stem  or  root-stock.  In  most  cases,  however,  per- 
ennial plants  take  care  to  keep  over  their  live 
material  from  one  season  to  the  other  by  some 
such  means  of  permanent  storage.  They  are,  so 
to  speak,  capitalists.  Natural  selection  has  of 
course  preserved  those  plants  w^hich  thus  laid  by 
for  the  future,  and  has  killed  out  the  mere  spend- 
thrifts which  were  satisfied  to  live  for  the  fleeting 
moment  only.  The  soil  of  our  meadows  in  win- 
ter is  full  of  tubers,  bulbs,  and  root-stocks;  while 
our  shrubs  and  trees  carry  over  their  capital  from 
season  to  season  in  their  living  bark,  secure  from 
injury.  In  one  way  or  another  all  our  perennial 
plants  manage  to  tide  their  living  green-stuff,  or 
at  least  its  raw  material,  by  hook  or  by  crook, 
over  the  dangers  of  winter. 

I  have  given  so  much  space  to  the  subject  of 
leaves  because,  as  you  must  see,  the  leaf  is  really 
the  most  important  and  essential  part  of  the  en- 
tire plant — the  part  for  whose  sake  all  the  rest 
exists,  and  in  which  the  main  work  of  making 
living  material  out  of  lifeless  carbonic  acid  and 
water  is  concentrated. 


HOW   PLANTS   DRINK.  53 

Let  us  sum  up  briefly  the  main  facts  we  have 
learned  in  this  long  chapter. 

Plants  eat  carbonic  acid  under  the  influence 
of  sunlight.  They  store  up  the  solar  energy  thus 
derived  in  starches  and  green-stuff  in  their  own 
bodies.  Very  simple  plants,  which  float  freely  in 
water,  eat  and  drink  with  all  portions  of  their 
surface.  But  higher  plants  eat  with  special  or- 
gans. These  organs  are  known  as  leaves,  and 
are  the  parts  where  the  chief  business  of  the 
plant  is  transacted. 

A  leaf  is  an  expanded  mass  of  cells,  containing 
living  green-stuff,  supported  on  a  tougher  frame- 
work, or  rib-like  skeleton.  Leaves  take  in  car- 
bonic acid  by  means  of  tiny  absorbing  mouths, 
which  exist  on  their  upper  surface ;  and  they 
turn  loose  most  of  the  oxygen,  by  the  aid  of  sun- 
light, building  up  the  carbon  into  starch,  with 
hydrogen  from  the  water  supplied  by  the  roots  to 
them.  Leaves  are  of  different  shapes,  according 
to  the  work  they  have  to  do  for  the  plant  in 
different  situations.  Where  carbon  and  sunlight 
abound  they  are  round,  or  nearly  so ;  where  car- 
bon and  sunlight  are  scanty,  or  much  competed 
for,  they  are  more  or  less  divided  into  minute 
sections. 


CHAPTER   V. 

HOW    PLANTS    DRINK. 

We  have  now  learnt  that  plants  really  eat  for 
the  most  part  with  their  leaves.  They  grow,  on 
the  whole,  out  of  the  air,  not,  as  most  people 
seem  to  fancy,  out  of   the  soil.     Yet  you   must 


54  THE   STORY  OF  THE   PLANTS. 

have  noticed  that  farmers  and  gardeners  think  a 
great  deal  about  the  ground  in  which  they  plant 
things,  and  very  little,  apparently,  about  the  air 
around  them.  What  is  the  reason  for  this  curi- 
ous neglect  of  the  real  food  of  plants,  and  this 
curious  importance  attached  to  the  mould  or  soil 
they  root  in  ? 

That  is  the  question  we  shall  have  to  consider 
in  the  present  chapter ;  and  1  shall  answer  it  in 
part  at  once  by  saying  beforehand  that,  though 
plants  do  grow  for  the  most  part  out  of  the  car- 
bonic acid  supplied  by  the  air  to  the  leaves,  they 
also  require  certain  things  from  the  soil,  less  im- 
portant in  bulk,  but  extremely  necessary  for  their 
growth  and  development.  What  they  eat  through 
their  leaves  is  far  the  greatest  in  amount ;  but 
what  they  drink  through  their  roots  is  neverthe- 
less indispensable  for  the  production  of  that  liv- 
ing green-stuff,  chlorophyll,  which,  as  we  saw,  is 
the  original  manufacturer  and  prime  maker  of  all 
the  material  of  life,  either  vegetable  or  animal. 

Plants  have  roots.  These  roots  perform  for 
them  two  or  three  separate  functions.  They  fix 
the  plant  firmly  in  the  soil ;  they  suck  up  the 
water  which  circulates  in  the  sap ;  and  they  also 
gather  in  solution  certain  other  materials  which 
are  necessary  parts  of  the  plant's  living  matter. 

The  first  and  most  obvious  function  of  the 
root  is  to  fix  the  plant  firmly  in  the  soil  it  grows  in. 
Very  early  floating  plants,  of  course,  have  no 
roots  at  all ;  they  take  in  water  and  the  dissolved 
materials  it  contains,  with  every  part  of  their 
surface  equally,  just  as  they  take  in  carbonic 
acid  with   every  part   of   their   surface   equally. 


HOW   PLANTS   DRINK.  55 

They  are  all  root,  all  leaf,  all  flower,  all  fruit. 
But  higher  plants  tend  to  produce  different  or- 
gans, which  have  become  specially  adapted  by 
natural  selection  for  special  purposes.  If  you 
sow  a  pea  or  bean  you  will  find  at  once  that  the 
young  seedling  begins  from  the  very  first  to  dis- 
tinguish carefully  between  two  main  parts  of  its 
body.  In  one  direction,  it  pushes  downward, 
forming  a  tiny  root,  which  insinuates  itself  with 
care  among  the  stones  and  soil ;  in  the  other 
direction,  it  pushes  upward,  forming  a  baby  stem, 
which  gradually  clothes  itself  with  leaves  and 
flowers. 

The  tip  of  the  root  is  the  part  of  the  plant 
which  exercises  the  greatest  discrimination  and 
ingenuity,  so  much  so  that  Darwin  likened  it  to 
the  brain  of  animals.  For  it  goes  feeling  its  way 
underground,  touching  here,  recoiling  there,  in- 
sinuating little  fingers  among  pebbles  and  cran- 
nies, and  trying  its  best  by  endless  offshoots  to 
fix  the  plant  with  perfect  security.  Large  trees, 
in  particular,  need  very  firm  roots,  to  moor  them 
in  their  places,  and  withstand  the  force  of  the 
winds  to  which  they  are  often  subject.  After 
every  great  storm,  as  we  know,  big  oaks  and 
pines  may  be  seen  uprooted  by  the  power  of  this 
invisible  but  very  dangerous  enemy. 

The  root,  however,  does  not  serve  merely  to 
anchor  the  plant  to  one  spot,  and  secure  it  a 
place  in  which  to  grow  and  feed ;  it  also  drinks 
water.  The  hairs  .  and  tips  of  the  root  absorb 
moisture  from  the  soil ;  and  this  water  circulates 
freely  as  sap  through  the  entire  plant,  dissolving 
and  carrying  with  it  the  starches  and  other  ma- 
terials which  each  part  requires  for  its  growth  and 


56        THE  STORY  OF  THE  PLANTS. 

nourishment  (Figs.  7,  8,  and  9).     Without  water, 
as  we  all  know,  plants  will  wither   and   die;  and 

the  roots  push  down- 
ward and  outward  in 
every  direction  in 
search  of  this  neces- 
sary of  life  for  the 
leaves  and  flowers. 

In  addition  to  these 
two  functions  of  fixing 
the  plant  and  drinking 
water,  however,  roots 
perform  a  third  and  al- 
most more  important 
one  in  absorbi7ig  the  oth- 
er needful  materials 
of  plant  life  from  the 
soil  about  them.  They 
drink,  not  water  alone, 
but  other  things  dis- 
solved in  it. 

What  are  these  oth- 
'  /    „         -,.'         er  things?     Well,  the 

Fig.  7.  Fig.  8.  Fig.  o.  ^       .1     ^ 

^  ^  ^      answer   to   that   ques- 

FiG  7.-Root  of  the  carrot.    Fig.    tion   will  fairly  round 

8. — Root  of  the  frogbit,  floating       rr  r-      ^  u  •  j 

in  water.    Fig.  g.-Root  of  thi   off  our  first  rough  idea 

radish.    The  small  hair-Uke  ends    of     the     raw    materials 

food^saUs."^^^^'  ^""^  ^^^^«i^^d   that    life   is   made  up 

from.  We  saw  already 
that  plants  eat  carbon  and  hydrogen  from  the  air 
and  water;  out  of  these  they  manufacture  a  large 
number  of  compounds,  such  as  starches,  oils, 
sugars,  and  so  forth,  all  of  which  contain  a  little 
oxygen,  but  far  less  than  the  amount  contained  in 
the  carbonic  acid  and  water  from  which  they  are 


HOW    PLANTS    DRINK.  57 

manufactured.  These  useful  materials,  however, 
though  possessing  energy,  that  is  to  say  the  power 
of  producing  light  and  heat  and  motion,  are  not 
exactly  live-stuffs;  in  order  to  make  out  of  them 
the  living  green  matter  of  leaves,  chlorophyll,  or 
the  living  cell-stuff  of  all  bodies,  animal  or  vege- 
table, protoplasm,  we  must  have  a  fourth  element^ 
nitrogen  ;  and  that  element  is  supplied  by  the  roots 
in  solution. 

So  now  you  see  the  full  importance  of  the 
roots  ;  they  add  to  the  oils  and  starches  manu- 
factured in  the  leaves  that  mysterious  body,  ni- 
trogen, which  is  necessary  in  order  to  turn  these 
things  into  protoplasm  and  chlorophyll. 

A  few  other  things  besides  nitrogen  are  also 
needed  by  the  plant  from  the  soil ;  the  most  im- 
portant of  these  are  sulphur  and  phosphorus. 
The  plant,  however,  does  not  take  in  these  sub- 
stances in  their  free  or  simple  form,  as  nitrogen, 
sulphur,  and  phosphorus,  but  in  composition,  as 
soluble  nitrates,  sulphates,  and  phosphates. 

Now,  I  am  not  going  to  trouble  you  with  a 
long  chemical  account  of  how  the  plant  combines 
these  various  materials — a  thing  about  which 
even  chemists  and  botanists  themselves  know  as 
yet  but  very  little.  It  will  be  enough  to  say  here 
that  the  plant  builds  them  up  at  last  into  an  ex- 
tremely complex  body,  called  protoplasm ;  and 
this  protoplasm  is  the  ultimate  living  matter,  the 
"  physical  basis  of  life ;  "  the  thing  without  which 
there  could  be  no  plants  or  animals  possible. 

What  is  protoplasm — this  mysterious  stuff, 
which  builds  up  the  bodies  of  plants  and  animals  ? 
It  is  a  curious  transparent  jelly-like  substance, 
full  of  tiny  microscopic  grains,  and  composed  of 


58        THE  STORY  OF  THE  PLANTS. 

carbon,  hydrogen,  oxygen,  nitrogen,  and  sulphur. 
Sometimes  it  is  almost  watery,  sometimes  half- 
horny,  but  as  a  rule  it  is  waxy  or  soft  in  texture. 
It  is  very  plastic.  Its  peculiar  characteristic  is 
that  it  is  restlessly  alive,  so  to  speak;  seen  under 
a  microscope,  it  moves  about  uneasily,  with  a 
strange  streaming  motion,  as  if  in  search  of  some- 
thing it  wanted.  It  is,  in  point  of  fact,  the  build- 
ing-material of  life;  and  out  of  it  the  living  parts 
of  every  creature  that  lives,  whether  animal  or 
vegetable,  are  framed  and  compounded. 

But  it  is  plants  alone  that  know  how  to  make 
protoplasm,  or  other  organic  matter,  direct  from 
the  dead  material  around  them.  Animals  can  only 
take  living  matter  ready-made  from  plants,  and 
burn  it  up  again  by  reunion  with  oxygen  in  their 
own  bodies.  The  plant  manufactures  it.  The  ani- 
mal destroys  it.  Chlorophyll  bodies  or  the  active 
green-stuff  of  leaves  is  a  special  modification  or  va- 
riety of  protoplasm  ;  and  chlorophyll  alone  pos- 
sesses the  power  to  manufacture  new  energy- 
yielding  and  living  material,  under  the  influence  of 
sunlight,  from  the  dead  and  inert  bodies  around  it. 
The  materials  which  it  thus  produces  are  after- 
wards worked  up  by  the  plant,  together  with  the  ni- 
trogen, sulphur,  and  phosphorus  supplied  by  the 
roots,  into  fresh  starch  and  fresh  protoplasm,  con- 
taining fresh  chlorophyll.  These  the  animal  may 
afterwards  eat  in  the  form  of  leaves,  seeds,  or  fruits. 

The  tiniest  primitive  one-celled  plant  contains 
protoplasm  and  chlorophyll  (though  a  few  degen- 
erate plants,  like  fungi,  have  none  of  the  living 
green-stuff,  and  can  make  no  new  living  material 
for  themselves,  but  depend,  like  animals,  upon  the 
industry  of  others).  Every  living  cell  of  every 
plant  contains  protoplasm ;  a  cell  without  any  is 


HOW   PLANTS   DRINK.  59 

dead  and  lifeless.  Protoplasm,  in  short,  is  the 
only  living  material  7vc  know  ;  and  its  life  constitutes 
the  larger  life  of  the  wholes  compounded  of  it. 

Well,  now  you  are  in  a  position  to  see  why  the 
farmer  and  the  gardener  attach  so  much  impor- 
tance to  the  soil,  and  so  little,  apparently,  to  the 
air  and  the  sunlight.  The  reason  is  that  the  air 
is  everywhere;  you  get  it  for  nothing;  but  the 
soil  costs  money,  and,  when  cultivated,  it  requires 
to  be  supplied  from  time  to  time  with  fresh  stores 
of  the  particular  materials  the  plants  take  from  it. 

Let  me  give  two  simple  parallel  cases.  A  fire 
is  made  by  the  combination  of  two  sorts  of  fuel — 
coal  and  oxygen.  One  is  just  as  necessary  for 
fire-making  as  the  other.  But  we  buy  coal  dear, 
and  we  neglect  to  take  oxygen  into  consideration 
accordingly.  The  reason  is  that  oxygen  exists 
in  abundance  everywhere;  so  we  don't  have  to 
buy  it.  If  we  paid  a  pound  a  ton  for  it,  as  we  do 
with  coal,  we  should  very  soon  remember  how 
necessary  a  part  it  is  of  every  fire.  Even  at  pres- 
ent we  are  obliged  to  provide  for  its  free  admis- 
sion by  the  bars  of  the  grate,  and  by  checking  or 
regulating  its  ingress  we  can  slacken  or  quicken 
the  burning  of  the  fire. 

Or,  to  take  another  analogy,  oxygen  is  just  as 
necessary  to  human  beings  and  other  animals  as 
food  and  drink  are.  But,  as  a  rule,  we  get  oxygen 
everywhere  in  such  great  abundance  that  we  never 
think  of  taking  it  into  practical  consideration. 
Still,  in  the  Black  Hole  of  Calcutta,  the  unhappy 
prisoners  thoroughly  reahsed  the  full  value  of 
oxygen,  and  would  gladly  have  paid  its  weight  in 
gold  for  the  life-giving  element. 

Now,  carbonic  acid,  on  which   plants   mainly 


6o  THE   STORY  OF  THE   PLANTS. 

live,  is  not  so  common  or  so  abundant  a  gas  as 
oxygen ;  but  still,  it  exists  in  considerable  quanti- 
ties in  the  air  everywhere.  So  most  plants  are 
able  to  get  almost  as  much  as  they  need  of  it. 
Nevertheless,  submerged  plants,  and  plants  that 
grow  in  very  crowded  places,  seem  to  compete 
hard  with  one  another  for  this  aerial  food ;  and  in 
certain  cases  they  appear  to  live,  as  it  were,  in  a 
very  Black  Hole  of  Calcutta,  so  far  as  regards  the 
supply  of  this  necessary  material.  In  farms  and 
gardens,  however,  the  farmer  takes  care  that  every 
plant  shall  have  plenty  of  room  and  space — in 
other  words,  free  access  to  sunlight  and  carbonic 
acid.  He  "  gives  the  plants  air,"  as  he  says,  not 
knowing  that  he  is  really  supplying  them  with 
their  aerial  food-stuff.  He  does  this  by  keeping 
down  weeds — by  ploughing,  by  digging,  by  hoe- 
ing, by  tilling.  Indeed,  what  do  we  really  mean 
by  cultivation  ?  Nothing  more  than  destroying 
the  native  vegetation  of  a  place,  in  order  to  make 
room  for  other  plants  that  we  desire  to  multiply. 
We  plough  out  the  grasses  and  herbs  that  occupy 
the  soil ;  we  sow^  or  plant  thinly  seeds  or  cuttings 
of  corn  or  vines  or  potatoes  that  we  desire  to 
propagate.  We  give  these  new  plants  plenty  of 
space  and  air — in  other  words,  free  access  to  sun- 
light and  carbonic  acid.  And  that  is  the  funda- 
mental basis  of  cultivation — to  keep  down  certain 
natural  plants  of  the  place,  in  order  to  give  free 
room  to  others. 

But  as  the  crop-plants  require  to  root  them- 
selves, the  farmer  naturally  thinks  most  of  the 
soil  they  root  in — which  he  has  to  buy  or  rent, 
while  the  carbonic  acid  comes  freely  to  him,  un- 
perceived,  with  the  breath  of  heaven.  Where 
water  is  scarce,  as  in  irrigated  desert  lands,  the 


HOW   PLANTS   DRINK.  6 1 

farmer  recognises  quite  equally  the  importance  of 
water.  But  he  never  recognises  the  true  impor- 
tance of  carbonic  acid.  That  is  why  most  people 
wrongly  imagine  that  plants  grow  out  of  the  soil, 
not  out  of  the  air.  Still,  when  we  burn  them,  the 
truth  becomes  clear.  The  portion  of  the  plants 
derived  from  air  and  water  goes  off  again  into 
the  air  in  the  act  of  burning  :  so  too  does  the 
nitrogen :  the  remaining  portion  derived  direct 
from  the  soil  is  only  the  insignificant  residue  re- 
turned to  the  soil  as  ash  when  we  burn  the 
plant  up. 

Nevertheless,  the  farmer  often  needs  to  sup- 
ply certain  raw  materials  to  the  soil  for  the  plants 
he  cultivates.  These  raw  materials  are  called 
manures ;  they  are  mostly  rich  in  nitrates  and 
phosphates ;  and  as  they  are  usually  the  only 
things  directly  supplied  to  plants  by  human 
agency — the  carbonic  acid  and  water  being  sup- 
plied by  wind  and  rain  in  the  ordinary  course  of 
nature — they  help  to  strengthen  the  popular  mis- 
apprehension that  plants  grow  directly  out  of  the 
soil.  Manures  consist  chiefly  of  compounds  of 
nitrogen,  phosphorus,  and  potash.  These  are  the 
things  of  which  the  plants  take  most  from  the 
soil  ;  and  when  the  crops  are  cut  down  and  car- 
ried away,  it  becomes  necessary  to  restore  them. 
This  is  generally  done  by  means  of  farmyard 
manure,  bones,  or  guano.  Most  manures  are 
really  the  remains  or  droppings  of  animals  ;  so 
that  when  we  lay  them  on  the  soil,  we  are  merely 
returning  to  it  in  another  form  what  the  animal 
took  from  it  when  he  ate  the  plants  up. 

All  plants,  however,  do  not  equally  exhaust 
the  soil  of  all  necessary  materials.     Some  require 


62  THE    STORY    OF   THE    PLANTS. 

one  sort  of  food,  and  others  another.  That  is 
why  farmers  have  recourse  to  what  is  called  7'ota- 
tion  of  crops^  so  as  to  follow  up  one  sort  of  plant 
in  a  field  by  another,  whose  needs  are  different. 
Thus  corn  is  alternated  with  swedes  or  turnips. 
Virgin  soil  will  produce  crops  for  several  seasons 
together  without  the  need  for  manuring ;  but 
when  many  crops  have  been  cut  from  it  in  suc- 
cession, the  earth  gets  exhausted  of  nitrates  and 
phosphates,  and  then  it  becomes  necessary  to 
manure  and  to  rotate  the  crops  in  the  ordinary 
manner. 

But  in  nature  crops  are  not,  as  a  rule,  removed 
from  the  soil ;  they  die  and  wither,  and  return  to 
it  for  the  most  part  whatever  they  took  from  it. 
The  dead  birds  and  insects,  and  the  droppings  of 
animals,  are  sufficient  manure  for  the  native  wood- 
land. Still,  even  in  nature,  certain  plants  more 
or  less  exhaust  the  soil  of  certain  valuable  ma- 
terials ;  and  therefore  natural  selection  has  se- 
cured a  sort  of  roundabout  rotation  of  crops  in  a 
way  of  which  I  shall  have  more  to  say  hereafter. 
Many  plants,  for  example,  which  greatly  exhaust 
the  soil,  have  winged  or  feathery  seeds  ;  and  these 
seeds  are  carried  by  the  wind  to  fresh  spots,  where 
they  alight  and  root  themselves,  in  order  to  es- 
cape the  exhausted  soil  in  the  neighbourhood  of 
their  mothers.  Other  plants  send  out  riumers,  as 
they  are  called,  on  long  trailing  branches,  which 
root  at  a  distance,  and  so  start  fresh  lives  in  ex- 
hausted places.  Yet  others  have  tubers,  which 
shift  their  place  from  year  to  year  ;  or  they  push 
forth  underground  suckers,  which  become  new 
plants  at  a  distance  from  the  parent.  All  these 
are  different  natural  ways  for  obtaining  what  is 
practically  rotation  of  crops  ;  nature  invented  that 


HOW   PLANTS   DRINK.  6;^ 

plan  millions  and  millions  of  years  before  it  was 
discovered  by  European  farmers. 

Moreover,  nature  sometimes  even  goes  in  for 
deliberate  manuring.  Plants  like  buttercups  and 
daisies,  that  live  in  ordinary  meadow  soils,  to  be 
sure,  get  enough  nitrogen  and  sulphur  and  other 
such  constituents  from  the  mould  in  which  they 
are  rooted.  But  in  very  moist  and  boggy  soils 
there  is  generally  a  lack  of  these  necessary  earth- 
given  elements  of  protoplasm;  and  natural  selec- 
tion has  therefore  favoured  any  device  in  the 
plants  which  grow  in  such  places  for  obtaining 
them  elsewhere.  This  they  do  as  a  rule  by  catch- 
ing insects,  killing  them,  sucking  their  juices,  and 
using  them  up  as  manure  for  manufacturing  their 
own  protoplasm  and  chlorophyll.  Our  pretty  little 
English  sundeiv  is  one  of  these  cruel  and  perfidious 
plants  (Fig.  lo).  Its  leaves  are  round,  and  thickly 
covered  with  small  red  hairs,  which  are  rather 
bulbous  at  the  end,  and  very  sticky.  The  bulbous 
expansions,  in  point  of  fact,  are  small  red  glands, 
which  exude  a  viscid  digestive  liquid.  When  a 
small  fly  alights  on  the  leaf,  attracted  by  the  smell 
of  the  sticky  fluid,  he  is  caught  and  held  by  its 
gummy  mass;  the  hairs  then  at  once  bend  over 
and  clutch  him,  pouring  out  fresh  slime  at  the 
same  time,  which  very  shortly  envelops  and  di- 
gests him.  In  the  course  of  a  few  hours  the  leaf 
has  sucked  the  poor  victim's  juices,  and  used  them 
up  in  the  manufacture  of  its  own  protoplasm. 

Many  other  insect-eating  plants  exist  in  the 
marshy  soils  of  other  countries.  One  of  the  best- 
known  is  the  Venus's  fly-trap  of  tropical  or  sub- 
tropical North  America.  In  this  curious  plant 
the  leaf  is  divided  into  two  portions,  one  of  which 


Fig,  io. — Sundew.  A  plant 
whose  leaves  eat  and  di- 
gest insects. 


HOW   PLANTS   DRINK.  65 

forms  a  jointed  snare  for  catching  insects.  It  is 
hinged  at  the  middle  ;  and  when  a  fly  lights  upon 
it,  the  two  edges  bend  over  upon  him,  and  the 
bristles  on  the  margin  interlock  firmly.  As  long 
as  the  insect  struggles  they  remain  tightly  closed  ; 
when  he  ceases  to  move,  and  is  quite  dead,  they 
open  once  more,  and  set  their  trap  afresh  for  an- 
other insect.  A  great  many  such  carnivorous  and 
insectivorous  plants  are  now  known  :  and  in  al- 
most every  case  they  inhabit  places  where  the 
marshy  and  waterlogged  soil  is  markedly  wanting 
in  nitrogen  compounds.  Insect-eating  leaves  are 
thus  a  device  to  supply  the  plant  with  nitrogen 
by  means  of  its  foliage,  in  circumstances  where 
the  roots  prove  powerless  for  that  purpose. 

Simpler  forms  of  the  same  sort  of  habit  may 
be  seen  in  many  other  familiar  plants.  Thus  our 
English  catchflies  and  several  other  of  our  com- 
mon weeds  have  sticky  glandular  stems,  which 
exude  a  viscid  secretion,  by  whose  aid  they  catch 
and  digest  flies.  This  is  the  beginning  of  the  in- 
sect-eating habit,  more  fully  evolved  by  natural 
selection  in  marsh-plants  like  sundew,  and  espe- 
cially in  larger  subtropical  types  like  the  Venus's 
fly-trap.  If  you  collect  English  wild-flowers  you 
will  soon  perceive  that  a  great  many  of  them  have 
sticky  glands  on  the  summit  of  the  stem,  near  the 
flowering  heads  ;  and  this  is  useful  to  them,  be- 
cause the  flowers  and  seeds  are  particularly  in 
want  of  nitrogenous  matter  for  the  pollen  and 
ovules  and  the  development  of  the  seed.  In  short, 
though  plants  get  their  nitrogen  mainly  by  means 
of  the  roots,  they  often  lay  in  a  supplementary 
store  by  their  stems  and  their  foliage. 

Our  common  English  teasel  shows  us  the  be- 
ginnings of  another  form  of  insect-eating,  which 
5 


66  THE  STORY  OF  THE   PLANTS. 

is  highly  developed  in  certain  American  and  Asi- 
atic marsh-plants.  The  leaves  of  teasel  grow  op- 
posite one  another,  joining  the  stem  at  the  base, 
so  as  to  form  between  them  a  sort  of  cup  or  basin, 
which  will  hold  water.  If  you  look  close  into  this 
water  you  will  find  that  it  is  often  full  of  dead 
midges  and  ants ;  and  the  plant  puts  forth  long 
strings  of  living  protoplasm  into  the  water,  which 
suck  up  the  decaying  juices  of  these  insects,  and 
use  them  for  the  manufacture  of  more  protoplasm 
and  chlorophyll.  In  this  case,  water  is  used  both 
as  a  trap  and  as  a  solvent ;  the  insects  are  first 
drowned  in  the  moat,  and  then  allowed  to  decay 
and  digest  themselves  in  it. 

Teasel,  however,  is  but  a  simple  example  of 
this  method  of  insect-catching.  Several  American 
marsh-dwellers,  collectively  known  as  pitcher- 
plants^  carry  the  same  device  a  great  deal  further. 
They  are  far  more  advanced  and  developed  water- 
trap  setters.  The  Canadian  side-saddle  plant  allures 
insects  into  its  vase-shaped  leaves,  which  are  filled 
with  sugar  and  water.  This  is  just  the  same  plan 
which  Ave  ourselves  employ  to  catch  flies  when  we 
trap  them  in  a  glass  vessel  by  means  of  a  sweet- 
ened and  sticky  liquid.  The  pitchers  are  formed 
by  leaves  which  join  at  the  edges;  they  are  at- 
tractively coloured,  so  as  to  allure  the  flies;  and 
they  secrete  on  their  walls  a  honeyed  liquid,  which 
entices  the  victim  to  venture  further  and  further 
down  the  fatal  path.  But  the  inner  sides  of  the 
vase  are  set  with  stiff  downward-pointing  hairs, 
which  make  it  easy  to  go  on,  but  impossible  to 
crawl  back  again.  So  the  flies  creep  down,  eating 
away  at  the  sticky  sweet-stuff  as  they  go,  till  they 
reach  the  bottom  and  the  hungry  water,  when  they 
fall  in  by  hundreds,  and  are  drowned  and  digested. 


HOW   PLANTS   DRINK.  67 

I  have  found  these  plants  often  by  the  sides  of 
Canadian  bogs,  with  a  whole  seething  mass  of 
festering    and  decaying  insects    filling  up  every 


Fig.  II. — An  Australian  pitcher  plant  which  eats  insects. 

one    of    their   murderous   vases.      Other    pitcher- 
plants  are  found  in  Australia  (Fig.  11). 

The  Nepenthes  of  the  Malayan  Archipelago  is 
a  still  more  remarkable  water-trap  insect-eater,  in 
which  the  pitcher  is  formed  by  a  curious  jug-like 


68        THE  STORY  OF  THE  PLANTS. 

prolongation  at  the  end  of  the  leaf  (Fig.  12).  It 
is  provided  with  a  lid,  and  its  rim  secretes  a  sticky 
sweet  liquid.  Insects  that  enter  the  jug  are  pre- 
vented from  escaping  by  strong  recurved  hooks; 
and  these  hooks  are  so  powerful  that  at  times  they 
have  been  known  even  to  capture  small  birds  which 
had  incautiously  entered.  This  may  seem  curious, 
but  it  is  not  odder  than  the  fact  that  our  own  Eng- 
lish bladdenuort,  a  water  plant  with  pretty  yellow 
flowers,  which  grows  in  sluggish  streams,  has  sub- 
merged bladders  that  supply  it  with  manure,  not 
only  from  water-beetles,  larvae,  and  other  insects, 
but  also  from  trout  and  other  young  fry  of  fresh- 
water fishes.  I  may  add  that  while  the  sundew 
and  other  live-insect  catchers  have  to  digest  their 
prey,  the  water-trap  makers  save  themselves  that 
additional  trouble  and  expense  by  macerating  and 
soaking  it  till  it  reaches  the  condition  of  a  liquid 
manure,  ready  dissolved  for  absorption,  and  easy 
to  assimilate. 

Thus  we  see  that  while  roots  are  the  chief  or- 
gans for  absorbing  nitrogenous  matter,  they  are 
often  supplemented  in  special  circumstances  by 
leaves  and  stems.  Moreover,  in  many  cases  leaves 
also  supply  the  plant  with  water.  On  the  other 
hand,  roots  often  fulfil  yet  another  function,  by 
storing  up  food  for  the  plant  from  one  season  to 
another.  It  is  true  this  is  still  more  often  done 
by  underground  stems,  but  the  distinction  betw^een 
the  two  is  very  technical,  and  I  do  not  think  I 
need  trouble  you  here  with  it.  Large  trees  with 
solid  trunks  usually  lay  by  their  starch  and  other 
valuable  materials  over  winter  in  a  peculiar  living 
layer  of  the  bark  ;  and  here  it  is  on  the  whole 
fairly  free  from  danger.     Still,  even  in  trees  the 


Fig.  12. — Insect-eating  pitchers  of  the  Malayan  nepenthes. 


70        THE  STORY  OF  THE  PLANTS. 

lower  part  of  the  bark  is  often  nibbled  by  such 
animals  as  rabbits;  and  to  prevent  this  mischance 
most  smaller  plants  bury  their  rich  food-stuffs 
underground  during  the  cold  season.  For  what- 
ever will  feed  a  young  plant  or  a  growing  shoot 
will  also  just  equally  feed  an  animal.  Hence  the 
frequency  with  which  plants  make  hoards  of  their 
collected  food-stuffs  underground,  for  use  next 
season.  The  potato  is  a  well-known  instance  of 
such  underground  hoards  ;  the  plant  lays  by  in 
what  are  technically  subterranean  branches  a  sup- 
ply of  food-stuff  for  next  season's  growth.  These 
branches  are  covered  with  undeveloped  buds, 
which  the  farmer  calls  "eyes";  and  from  each  of 
these  eyes  (if  the  potato  is  left  undisturbed,  as 
nature  meant  it  to  be)  a  branch  or  stem  will  start 
afresh  next  season.  It  will  use  up  the  starch  and 
other  foodstuffs  in  the  potato,  till  it  reaches  the 
light ;  and  there  it  wnll  begin  to  develop  green 
chlorophyll,  and  to  make  fresh  starch  for  itself, 
and  young  leaves  and  branches. 

An  immense  number  of  plants  thus  lay  by 
underground  stores  of  food  for  next  season's  use. 
Such  are  the  carrot,  the  beet,  and  the  turnip.  And 
in  every  case  the  young  shoots  that  spring  from 
them  use  up  the  starches  and  other  food-stuffs  at 
first  exactly  as  an  animal  would  do.  These  stores 
are  often  protected  against  animals  by  hard  coats 
of  poisonous  juices.  Many  well-known  examples 
of  subterranean  stores  occur  among  our  spring 
garden  flowers,  which  are  for  the  most  part  either 
bulbous  or  tuberous.  The  material  laid  by  in  the 
bulb  allows  them  to  start  flowering  early,  while 
annuals  and  other  unthrifty  plants  have  to  wait 
till  they  have  collected  enough  material  in  the 
same    year    to    flower    upon.      Hyacinths,    tulips, 


HOW   PLANTS   DRINK.  7 1 

daffodils,  snowdrops,  crocuses,  and  the  various 
kinds  of  squills  and  jonquils  are  familiar  ex- 
amples of  plants  which  lay  by  in  one  year  ma- 
terial for  the  next  year's  flowering  season.  But 
our  wild  flowers  do  the  same  thing  quite  as  much, 
though  less  obtrusively.  Our  earliest  spring  but- 
tercup is  the  bulbous  buttercup,  which  has  a 
swollen  root-stock,  full  of  rich  material ;  and 
this  enables  it  to  flower  very  soon  indeed,  while 
the  fibrous  -  rooted  meadow  -  buttercup,  which 
closely  resembles  it  in  most  other  respects,  has 
to  wait  a  month  later,  and  then  to  raise  a  much 
taller  stem,  in  order  to  overtop  the  summer 
grasses,  which  by  that  time  have  reached  a  con- 
siderable height.  Still  earlier,  however,  is  an- 
other buttercup-like  plant,  the  lesser  celandine, 
which  has  material  laid  by  in  little  pill-like  tubers; 
and  these  have  given  it  its  curious  old  English 
name  of  pilewort.  Other  early  spring  wild- 
flowers  are  the  wood  anemone  and  marsh-mari- 
gold, with  rich  and  thick  almost  tuberous  root- 
stocks ;  the  bulbous  wild  hyacinth,  the  tuberous 
meadow  orchid,  and  the  common  arum,  or  "  lords 
and  ladies,"  with  its  starchy  root,  very  rich  in 
food-stuffs.  Indeed,  in  every  case'where  a  plant 
flowers  very  early  in  spring,  you  may  be  sure  the 
material  for  its  flowering  was  laid  up  by  the  plant 
in  the  previous  year — that  it  is  really  rather  a 
case  of  delayed  than  of  very  early  flowering. 

This  is  especially  true  of  trees,  like  the  black- 
thorn or  the  flowering  almond,  where  the  flower- 
buds  are  usually  formed  over  winter,  and  only 
fully  developed  in  the  succeeding  spring.  The 
same  thing  happens  with  gorse ;  only  here,  a  few 
bushes  always  break  into  bloom  in  October  or 
November,  while  others  burst  spasmodically  into 


72  THE   STORY   OF   THE    PLANTS. 

blossom  whenever  a  warm  and  sunny  spell  occurs 
in  January  or  February.  The  remaining  bushes 
are  covered  through  the  winter  with  hairy  brown 
buds,  and  burst  out  in  early  spring  into  golden 
masses  of  scented  blossom.  A  like  arrangement 
also  occurs  in  many  catkins,  which  are  the  flowers 
of  certain  trees;  the  catkins  of  the  birch  and  the 
alder,  for  example,  are  always  formed  in  early 
autumn,  though  they  only  break  into  bloom  with 
recurring  warmth  in  March  or  April. 

We  have  travelled  away  so  far  from  our  origi- 
nal question  of  How  plants  dtink,  that  a  sum- 
mary of  this  chapter  is  even  more  necessary  than 
usual. 

Plants  drink  by  means  of  roots.  But  they 
take  up  by  them,  not  only  water,  which  is  their 
needful  solvent,  but  also  other  materials  urgently 
required  for  their  growth  and  development.  The 
most  important  of  these  materials  is  certainly 
nitrogen,  which  forms  an  indispensable  compo- 
nent of  protoplasm  and  chlorophyll.  Where,  how- 
ever, the  roots  do  not  supply  nitrogenous  matter 
in  sufficient  quantities,  plants  procure  it  for  them- 
selves by  means  of  their  leaves  or  stems,  and 
therefore  become  insect-eSting  or  flesh-eating. 
Soils  get  exhausted  at  times  of  nitrates,  phos- 
phates, and  other  necessary  materials  of  plant- 
life.  The  farmer  meets  this  difficulty  by  manur- 
ing, and  by  rotation  of  crops.  Nature  meets  it 
by  dispersion  of  seeds.  Roots,  however,  have 
other  functions  besides  drinking  water  and  suck- 
ing up  with  it  certain  dissolved  materials;  the 
chief  of  these  other  functions  are  fixing  the  plant 
securely  in  the  ground,  and  affording  a  safe  place 
of  winter  storage  for  starches  and  other  surplus 


HOW   PLANTS   MARRY.  73 

food-stuffs.  Many  plants  die  down  almost  en- 
tirely, above  ground,  in  winter,  and  keep  their 
raw  material  in  underground  reservoirs,  most  of 
which  are  stem-like  rather  than  root-like.  Ani- 
mals, however,  find  out  these  subterranean  re- 
serves, and  prey  upon  them ;  hence  the  plants 
often  secure  their  hoard  by  nauseous  tastes  or 
other  protective  devices. 


CHAPTER   VI. 

HOW    PLANTS    MARRY. 

We  next  come  to  what  is  perhaps  the  most 
fascinating  chapter  of  all  in  the  life-history  of 
plants— the  chapter  which  tells  us  how  they  marry 
and  are  given  in  marriage. 

In  order  that  you  may  fully  understand  this 
curious  and  delightful  subject,  however,  I  shall 
have  to  begin  by  telling  you  a  few  preliminary 
points  less  interesting  in  themselves,  and,  I  fear, 
at  times  not  a  little  troublesome. 

Flowers  are  the  husbands  and  wives  of  plants. 
And  in  some  plants  the  sexes  are  as  fully  sepa- 
rated as  in  birds  or  beasts ;  when  once  you  know 
them,  you  can  distinguish  at  sight  a  male  from  a 
female  flower  as  readily  as  you  can  distinguish  a 
bull  from  a  cow,  or  a  peacock  from  a  peahen  (Fig. 
13).  But  in  other  cases  the  sexes  are  muddled  up 
in  the  same  blossom  or  on  the  same  plant  in  a 
way  that  makes  it  rather  difficult  to  understand 
their  true  nature  without  a  little  pains  and  some 
close  attention. 

So  we  must  go  back  a  bit  for  light  to  the  lower 
plants.     Here  we  find  no  flowers  at  all,  and  in 


74 


THE  STORY   OF   THE   PLANTS. 


Fig.  13.— a,  male,  and  B,  female  flower 
of  a  sedge,  much  magnified.  The 
sexes  are  here  quite  distinct  and  un- 
like. 


the  very  lowest  cases  of  any  nothing  in  the  least 
resembling  a  blossom.    Very  simple  plants,  in  fact, 

have  two  ways  of 
reproducing.  The 
earliest  way  is, 
when  a  single  cell 
divides  in  the  mid- 
dle, to  form  two 
others ;  a  some- 
what less  primi- 
tive way  is  when  a 
single  cell  breaks 
suddenly  up,  and 
produces  from  it- 
self a  whole  swarm 
of  young  ones.  In 
both  these  ways, 
however,  there  is 
no  trace  of  sex  ;  only  one  single  cell  is  concerned 
in  the  process  ;  the  plants  have  a  mother,  perhaps, 
but  certainly  not  a  father. 

The  thread-like  pond-weeds,  however,  which 
are  slightly  higher  plants  in  the  scale  of  being 
than  the  single-celled  floating  types,  show  us  the 
first  beginnings  of  something  like  plant-marriage. 
These  hair-like  little  weeds  consist  each  of  a  single 
thread  or  string  of  cells,  placed  end  on  end  to- 
gether, like  beads  or  pearls  in  a  necklet,  and  con- 
taining green  chlorophyll.  You  can  find  them  in 
almost  any  stagnant  pond  in  spring,  where  they 
cling  to  the  side  in  soft  greenish  moss-like  or  vel- 
vety masses.  But  if  you  examine  one  slimy  string 
under  a  microscope,  you  will  see  a  curious  thing 
often  happening  between  the  threads  of  two  such 
hair-like  plants.  As  they  grow  side  by  side,  two 
of  the  strings  will   sometimes  range  themselves 


HOW    PLANTS    MARRY. 


75 


just  parallel  to  one  another,  with  their  cells  facing 
(Fig.  14).  Then  each  opposite  pair  of  cells  begins 
to  bulge  a  little  at  the  point  where  they  nearly 
touch  {a  and  ^  in  the  figure),  till  at  last  they  join 
and  coalesce  with  one  another  (c  and  d  in  the  fig- 
ure). The  contents  of  one  cell  pass  into  another 
(at  e),  and  the  two  form  a  sort  of  egg  (/),  which 
lies  quiet  for  a  while,  and  then  buds  out  into  a 
new  thread  or  hair-like  plant  by  division.  In  this 
strange  process  we  have  the  beginning  of  sex — 
the  first  hint  of  plant  and  animal  marriages. 

What  is  the  meaning  and  good  of  it  ?  Why  do 
the  plants  act  thus  ?  That  question  we  don't  yet 
quite  understand,  perhaps;  but  this  seems  to  be 
in  part  at  least  its  reason.  Proto- 
plasm requires  to  be  kept,  as  it 
were,  perpetually  young  and  ever 
fresh;  it  cannot  afford  to  lose  its 
elasticity  and  its  plasticity.  If  it 
does,  it  grows  old  in  time  and  dies. 
To  prevent  this  misfortune,  and 
the  death  of  all  things,  plants  and 
animals  have  invented  all  sorts  of 
curious  expedients;  for  example, 
the  protoplasm  of  a  living  cell 
sometimes  breaks  out  of  the  cell- 
wall,  and  undergoes  a  process  which 
is  called ''  rejuvenescence,"  or groiu- 
ing  young  agaiti.  It  lies  quiet  for 
awhile  in  its  free  condition,  and 
then  begins  to  build  up  a  new  wall 
afresh  for  itself.  It  seems  by  the  process  of 
breaking  out  to  have  gained  for  itself  a  new  lease 
of  life,  as  we  ourselves  often  do  by  a  trip  abroad 
or  change  of  sea  and  air  and  occupation.  How- 
ever  this  may  be,  it  is  certain  at  least  that  the 


Fig.  14.— Begin- 
nings of  sex  in 
a  pond  weed, 
very  much  mag- 
nified. 


76        THE  STORY  OF  THE  PLANTS. 

union  of  two  cells  often  produces  a  fresher, 
stronger,  and  more  vigorous  young  one  than  can 
be  produced  by  mere  division  of  a  single  cell. 
In  some  way  or  other,  when  a  plant  or  animal 
reaches  maturity,  and  arrives  at  the  limit  of  its 
own  growth,  it  produces  stronger  and  livelier 
young  by  so  combining  with  another  of  its  own 
species. 

In  the  thread-like  pond-weeds  the  two  uniting 
cells  are  practically  similar.  They  are  not  dis- 
tinguished as  male  and  female.  Neither  of  them 
is  larger  or  smaller  than  the  other;  neither  of 
them  is  more  active  or  more  vigorous  than  its 
consort.  But  in  the  higher  plants  a  marked  dif- 
ference invariably  exists  between  the  two  cells 
that  join  to  form  the  new  individual — a  difference 
of  kind  ;  we  have  sex  now  appearing.  One  of 
the  cells  is  smaller,  and  more  active;  it  is  called 
a  ma/e  cell  or  polle?i-cell.  The  other  is  larger, 
richer,  and  more  passive;  it  is  called  di  fe??iale  cell^ 
or  ovule — that  is  to  say  in  plain  English,  a  little 
e%%.  Now  the  nature  of  the  ovule  is  such  that  it 
cannot  grow  out  into  a  seed  or  young  plant  till  it 
has  been  united  with  and  fertilised  by  the  smaller 
but  more  active  and  lively  pollen-cell. 

Separate  organs  in  the  higher  plants  always 
produce  the  pollen-grain  and  the  ovule.  These 
organs  are  known  as  stamens  and  pistils  (Fig. 
15).  They  are  really  separate  individuals,  or 
males  and  females.  The  stamen  is  the  father  of 
the  seed,  so  to  speak,  and  the  pistil  its  mother. 

This  is  a  hard  saying,  I  know,  and,  in  order 
that  you  may  understand  it,  I  must  begin  by  tell- 
ing you  another  point  about  the  plant  which  I 
have  hitherto  to  some  extent  studiously  con- 
cealed from  you.     It  is  this — each  higher  plant  is 


HOW   PLANTS   MARRY. 


77 


not  so  much  a  single  individual  as  a  community 
or  colony. 

A  hive  of  bees  will  help  you  to  understand 
this  difficult  paradox.  I  know  it  is  difficult ;  but, 
if  only  you  will  face  it,  it  will  throw  floods  of 
light  in  due  time  on  parts  of  our  subiect  we  must 
consider  hereafter. 
So  let  us  look  at  it 
close.  A  hive  is  a 
community.  It  con- 
sists for  the  most 
part  of  workers, 
who  are  practically 
neither  male  nor  fe- 
male. They  are 
neuters,  as  we  say  ; 
and  their  main  work 
is  to  find  food  for 
the  whole  hive,  in- 
cluding themselves 
and  the    grubs    or 

larvae  which  are  the  young  of  the  species.  But,  in 
addition  to  these  workers,  the  hive  has  a  queen, 
who  is  the  only  perfect  female,  or  mother,  and  who 
lays  the  eggs  from  which  the  larvae  are  produced ; 
and  it  has  also  several  drones,  who  are  the  males 
of  the  community,  and  fathers  of  the  larvae.  Thus 
we  have  a  colony  or  city,  as  it  were,  consisting  of 
a  few  males,  a  single  female,  and  a  whole  body  of 
worker  or  feeder  neuters. 

Now,  a  higher  plant,  like  a  cherry-tree  (to 
take  a  particular  example),  is  just  such  a  colony 
or  joint  community.  The  leaves,  each  of  which 
is  a  distinct  and  almost  self-supporting  individual, 
are  its  workers  and  feeders.  Like  the  worker 
bees,   too,  the   leaves  are  neuters — neither   true 


Fig.  15. — A  flower,  with  its  petals  re- 
moved. Outside  are  five  stamens, 
which  produce  pollen  :  in  the  centre 
is  the  pistil,  which  contains  the 
ovules  or  young  seeds. 


78  THE   STORY   OF  THE   PLANTS. 

males  nor  true  females.  They  feed  and  lay  by, 
and  from  them  new  leaves  are  continually  pro- 
duced in  the  buds  and  at  the  ends  of  branches. 
This  is  called  the  sexless  method  of  reproduction, 
and  it  is  essentially  similar  to  the  way  in  which 
the  single-celled  plant  or  the  simple  animal  di- 
vides itself  sexlessly  into  two  or  more  little  plant- 
lets  or  animals.  But,  in  addition  to  this  sexless 
way,  the  plant  also  at  certain  times  produces 
other  sorts  of  leaves  which  are  sexual  individuals, 
and  these  we  call,  in  the  lump,  flowers.  But 
flowers  are  not  all  alike  throughout.  They  con- 
sist of  certain  male  individuals,  the  stamens,  which 
answer  to  the  drones,  and  of  certain  female  indi- 
viduals, the  pistils  or  carpels,  which  answer  to  the 
queen  or  mother  bee,  and  produce  the  ovules  or 
little  eggs  of  the  family.  A  cherry-tree  is  thus  a 
plant-hive  or  colony,  consisting  for  the  most  part 
of  workers  or  leaves,  but  also  at  certain  times  of 
year  producing  male  and  female  members,  whose 
business  it  is  to  found  fresh  swarms,  as  it  were — 
to  produce  the  seeds  which  are  the  basis  and 
foundation  of  new  colonies. 

There  is  of  course  one  great  difference  be- 
tween a  hive  and  a  plant,  and  that  is  that  in  the 
hive  the  individuals  are  separate  and  distinct, 
while  in  the  plant  they  are  combined  on  a  single 
stem,  which  serves  to  join  them.  In  this  respect 
plants  are  more  like  a  branch  of  coral,  which  con- 
sists of  a  number  of  distinct  animals  or  polypes, 
united  by  a  core  of  stony  material,  and  a  living 
mass  of  connecting  matter.  Yet  the  difference 
between  the  leaves  and  the  bees  is  not  so  great 
as  at  first  sight  appears;  for  though  each  leaf 
does  not  as  a  rule  live  separately,  it  is  often 
capable  of  doing  so  if  occasion  arises.     A  single 


HOW   PLANTS   MARRY.  79 

leaf  of  stonecrop,  separated  from  the  parent 
plant,  will  root  itself  and  grow  into  a  fresh 
colony ;  and  in  some  plants,  like  begonias,  a 
single  fragment  of  a  leaf,  if  placed  on  wet  soil,  is 
capable  of  growing  out  into  a  new  individual. 
In  other  cases  small  leaves  drop  off  from  a  plant 
as  bulbils,  and  root  and  grow ;  while  in  others, 
again,  young  plants  sprout  out  from  the  edges 
of  old  leaves  to  form  new  colonies.  In  short, 
though  the  leaf  is  not  usually  a  distinct  plant, 
it  sometimes  is,  and  it  can  often  become  one  ;  it 
frequently  gives  rise  in  a  sexless  way  to  fresh 
plant  colonies.  A  graver  difficulty  is  this:  the 
plant  differs  from  the  hive  in  being  more  closely 
connected  and  subordinated  in  its  parts — the 
stem  and  root  (which  bind  and  unite  it),  bringing 
water  and  nitrogenous  matter,  while  the  leaves 
elaborate  the  starch  and  protoplasm  and  other 
chief  food-stuffs.  Even  this  difference,  however, 
is  less  grave  than  it  seems,  if  we  remember  that 
the  queen  bee  and  the  larvae  are  similarly  depend- 
ent upon  the  workers  for  food  and  protection. 
A  plant,  in  short,  is  a  colony  of  various  forms  of 
leaves,  very  closely  united  together  for  mutual 
service,  and  very  much  specialised  in  various 
ways  among  themselves  for  particular  functions. 

And  now  we  are  in  a  position  to  know  what 
work  the  flower  has  to  do  in  the  community.  It 
is  a  collection  of  special  and  peculiar  leaves,  told 
off  to  act  as  fathers  and  mothers  to  the  seeds, 
whence  are  to  be  born  future  plant  swarms  or 
future  colonies. 

A  flower,  in  its  simplest  form,  consists  of  a 
single  stamen  or  a  single  carpel — that  is  to  say, 
of  one  leaf  or  leaf-like  organ,  told  off  for  the  pro- 


8o        THE  STORY  OF  THE  PLANTS, 

duction  of  pollen  ;  or  of  one  leaf  or  leaf-like  or- 
gan, told  off  for  the  production  of  young  seeds 
or  ovules.  Flowers  as  simple  as  that  do  actually 
occur,  but  more  often  a  flower  is  much  more  com- 
plex, consisting  of  several  stamens  and  several 
carpels,  as  well  as  of  other  protective  or  attract- 
ive leaves,  often  highly  coloured  and  conspicu- 
ous, which  surround  or  envelop  these  essential 
organs. 

The  most  familiar  flowers,  as  we  actually  know 
them,  are  of  this  last  more  complex  type ;  each 
comprises  in  itself  several  male  and  several  female 
individuals.  The  male  individuals  are  stamens^  each 
of  which  generally  consists  of  two  little  pollen- 
bags,  called  the  anthei's,  and  a  rather  slender  stalk 
or  support,  known  as  the  filament.  The  female 
individuals  are  carpels,  each  of  which  generally 
consists  of  a  sort  of  sack  or  folded  leaf,  enclosing 
one  or  more  tiny  seeds  or  ovules. 

But  that  is  not  at  all  what  you  mean  by  a 
flower!  No;  certainly  not ;  and  half  the  flowers 
you  meet  in  a  morning's  walk  you  do  not  take 
for  flowers  at  all,  and  pass  by  unrecognised. 
Such  are  the  green  or  inconspicuous  blossoms  of 
the  grasses,  nettles,  oaks,  and  sedges,  as  well  as 
those  of  the  pines,  the  dog's  mercury,  the  spurge, 
and  the  hazel.  What  you  mean  most  by  a  flower 
is  a  mass  of  red  or  yellow  petals,  conspicuously 
arranged  about  the  true  floral  organs.  The  pet- 
als form,  in  point  of  fact,  the  popular  notion  of 
a  flower — though  from  the  point  of  view  of  science 
they  are  comparatively  unimportant,  and  are 
commonly  spoken  of  (with  the  calyx)  as  "the 
floral  envelopes."  It  is  the  stamens  and  pistils 
(or  carpels)  that  are  the  true  flowers;  they  do  the 
mass  of  the  real  work ;  and  an  enormous  number 


HOW   PLANTS   MARRY. 


8i 


of  flowers  possess  these  organs  alone,  without 
any  conspicuous  petals  or  other  coloured  sur- 
faces. 

However,  if  you  take  a  pretty  garden  flower 
(say  a  scarlet  geranium)  as  a  typical  example, 
and  begin  to  examine  it  from  the  centre  outward 
(which  is  the  truest 
way),  you  will  find 
it  consists  of  the 
following  parts,  in 
the  following  or- 
der : — 

In  the  very  cen- 
tre of  all  comes  the 
pistil^  consisting  of 
one  or  more  carpels, 
and  containing  the 
embryo  seeds  or 
ovules  (see  Fig.  15). 
Outside  this  part, 
and  next  in  order, 
come  the  stamens^ 
which  are  most  of- 
ten three  or  six  in 
one  great  group 
of  flowering  plants 
(the  lilies),  and  five, 
ten,  or  more  in  the 
other (the  roses  and 
buttercups).  The 
stamens  produce 
grains  of  pollen 
which  somehow  or  other,  either  by  means  of  the 
wind,  or  of  insects,  or  of  movements  on  the  part 
of  the  plant  itself,  are  sooner  or  later  applied  to 
the  sensitive  surface  or  stigma  of  the  pistil.  As 
6 


Fig.  16. — Grains  of  pollen,  very  much 
magnified,  sending  out  pollen-tubes. 


82 


THE  STORY   OF   THE   PLANTS. 


soon  as  a  pollen-grain  reaches  the  surface  of  the 
stigma,  it  is  held  there  by  a  sticky  secretion,  and 
instantly  begins  to  send  out  what  is  called  2ipollen- 
tiibe  (Fig.  i6).  This  pollen-tube  makes  its  way 
down  the  long  stem  or  style  which  joins  the  stigma 
to  the  ovary,  and  there  comes  in  contact  with  the 
undeveloped  ovules.  The  ovules  would  not  swell 
and  grow  into  seeds  of  themselves;  but  the  mo- 
ment the  pollen-tube  reaches  them,  they  quicken 


Fig.  17. — Flower  of  a  shrubbery  plant,  Weigelia,  with  the  petals 
united  into  single  corolla.  I,  entire  flower  ;  II,  the  same,  with 
part  of  the  corolla  cut  away  ;  III  and  IV,  a  stamen  :  k^  calyx  ; 
b^  corolla ;  s,  stamen  ;  a^  anther  of  the  stamen  ;  g  and  «,  parts 
of  the  pistil. 


into  life,  and  begin  to  develop  into  fertile  seeds. 
Unfertilised  ovules  wither  away  or  come  to  noth- 
ing, but  fertilisation  by  pollen  makes  them  de- 
velop at  once  into  new  plant  colonies. 

Outside  these  essential  organs^  as  botanists  call 
them,  however,  come,  in  handsome  garden  flowers, 
'  two  other  sets  of  organs,  more  leaf-like  in  appear- 
ance,  but   often   brightly   or    conspicuously    col- 


HOW   PLANTS  MARRY.  83 

oiired.  The  first  of  these  sets  of  organs,  going 
still  from  within  outward,  is  called  th^ petals,  or, 
collectively,  the  corolla.  Sometimes,  as  in  the 
dog-rose  or  the  buttercup,  the  corolla  consists  of 
five  separate  petals  ;  sometimes,  as  in  the  harebell 
and  the  gentian,  it  has  five  points,  or  lobes,  united 
at  the  base  into  a  single  piece  (Fig.  17).  Last  of 
all,  outside  the  corolla  again  comes  another  row 
or  layer,  called  the  calyx,  which  sometimes  con- 
sists of  five  separate  leaves  or  sepals,  as  in  the 
dog-rose  and  the  buttercup,  but  sometimes  has 
five  points,  welded  at  the  base  into  one  piece,  as 
in  red  campion  and  convolvulus.  It  is  these  last 
comparatively  unessential  but  very  conspicuous 
parts  that  most  people  think  of  when  they  say 
"  a  flower." 

What  is  their  use  ?  Well,  they  are  not  essen- 
tial, like  the  pistil  and  stamens,  because  many 
flowers,  perhaps  even  most  flowers,  do  without 
them  altogether.  But  they  are  very  useful  for 
all  that,  as  we  may  easily  guess,  because  they  are 
found  in  almost  all  the  most  advanced  and  devel- 
oped flowers.  The  use  of  the  corolla,  with  its  bril- 
liantly coloured  petals,  is  to  attract  insects  to  the 
flowers  and  induce  them  to  carry  pollen  from 
plant  to  plant.  That  is  why  they  are  painted  red 
and  blue  and  yellow;  they  are  there  as  advertise- 
ments to  tell  the  bee  or  butterfly,  "  Here  you  can 
get  good  honey."  The  use  of  the  calyx  is  usually 
to  cover  up  the  flower  in  the  bud,  to  keep  it  safe 
from  cold,  and  to  protect  it  from  the  attacks  of 
insect  enemies,  who  often  try  to  break  through 
and  steal  the  half-developed  pollen  in  the  bags  of 
the  stamens  before  it  is  ripe  and  ready  for  fer- 
tilising.    These  are  the  chief  uses  of  the  calyx  or 


84        THE  STORY  OF  THE  PLANTS. 

outer  cup  of  the  flower  ;  but,  as  we  shall  see  here- 
after, it  serves  many  other  useful  purposes  from 
time  to  time  in  various  kinds  of  flowers.  In  the 
fuchsia,  for  example,  it  is  quite  as  brilliantly  col- 
oured as  the  petals  of  the  corolla,  and  supple- 
ments them  in  the  work  of  attracting  insects.  In 
the  winter  cherry  or  Cape  gooseberry  it  forms  a 
brilliant  outer  envelope  or  covering  for  the  fruit, 
which  the  French  call  '■'■cerise  en  chemise^''  or 
"cherry  in  its  nightdress."  Other  uses  of  both 
calyx  and  corolla  will  come  out  by  and  by,  as  we 
proceed  to  examine  individual  instances. 

"  But  why,"  you  may  ask,  "  do  the  plants  want 
to  get  pollen  carried  from  plant  to  plant  ?  Why 
can't  each  flower  fertilise  itself  by  letting  its  pol- 
len fall  upon  its  own  pistil  ?"  Well,  the  question 
is  a  natural  one ;  and,  indeed,  many  flowers  do 
actually  so  fertilise  themselves  with  their  own 
pollen.  But  such  flowers  are  almost  always  poor 
and  degenerate  kinds,  the  unsuccessful  in  the 
race,  the  outcasts  and  street  arabs  of  plant  civili- 
sation. All  the  higher,  nobler,  and  more  domi- 
nant plants — the  plants  that  have  carved  out  for 
themselves  great  careers  in  the  world,  and  that 
occupy  the  best  posts  in  nature — have  invented 
some  mode  or  other  of  cross-fertilisation,  as  it  is 
called,  that  is  to  say  some  plan  by  which  the  pol- 
len of  one  plant  or  flower  fertilises  the  pistil  of 
another. 

What  does  this  mean  ?  Well,  regarding  the 
plant  as  a  colony,  you  will  see  at  once  that  the 
stamens  and  pistil  of  the  same  blossom  stand  to 
one  another  somewhat  in  the  relation  of  brothers 
and  sisters,  while  those  of  different  flowers  on  the 
same  plant  may  be  regarded  at  least  in  the  light 
of  first  cousins.     Now  the  very  same  thing  that 


HOW   PLANTS   MARRY.  85 

makes  sex  and  marriage  desirable,  makes  close 
intermarriage  of  blood  relations  undesirable. 
*'  Marrying  in  and  in,"  as  it  is  called,  tends  to 
produce  weak  and  feeble  offspring,  while  "  an  in- 
fusion of  fresh  blood  "  tends  to  make  both  plants 
and  animals  stronger  and  more  vigorous.  Hence, 
if  any  habit  chanced  to  arise  in  plants  which  fa- 
voured or  rendered  easier  such  cross-fertilisation, 
it  would  result  in  stronger  and  more  vigorous 
young,  and  would  therefore  be  fixed  by  natural 
selection.  The  actual  consequence  is  that  in 
the  world  of  plants,  as  we  see  it  to-day,  every 
great  dominant  or  successful  race  has  invented 
some  means  of  cross-fertilisation,  either  by  the 
agency  of  wind  or  of  insects,  while  only  the  mis- 
erable riff-raff  and  outcasts  of  plant-life  still  ad- 
here to  the  old  and  bad  method  of  fertilisation  by 
means  of  the  pollen  of  their  own  flowers. 

We  are  now  in  a  position  to  understand  the 
main  principles  which  govern  the  marriage  cus- 
tomsof  plants  ;  we  will  proceed  in  the  next  chap- 
ter to  consider  in  detail  how  these  principles  work 
out  in  particular  instances.  But  first  we  must  sum 
up  what  we  have  learnt  in  this  chapter. 

Plants  marry  and  are  given  in  marriage.  The 
very  lowest  plants,  indeed,  are  sexless,  but  in  the 
higher  there  are  well-marked  distinctions  of  male 
and  female.  An  intermediate  stage  exists  in  cer- 
tain thread-like  pond-weeds,  where  marriage  or 
intermixture  takes  place  between  two  adjacent 
cells,  neither  of  which  is  male  or  female.  The 
higher  plants,  however,  are  really  communities  or 
colonies,  of  which  the  leaves  are  the  workers,  and 
the  various  parts  of  the  flower  the  males  and 
females.     The  central  part  of  the  flower,  known 


86  THE   STORY  OF  THE   PLANTS. 

as  the  pistil,  is  the  female  individual ;  it  produces 
ovules,  or  young  seeds,  which,  however,  cannot 
grow  and  swell  without  the  quickening  aid  of  pol- 
len. The  next  row  in  the  flower,  known  as  the 
stamens,  contains  the  male  individuals;  they  pro- 
duce pollen,  which  lights  on  the  sensitive  surface 
of  the  pistil,  sends  out  tubes  of  very  active  living 
matter,  and  quickens  or  impregnates  the  ovules 
in  the  pistil.  Besides  these  necessary  organs  flow- 
ers have  often  two  other  sets  of  parts.  The  co- 
rolla, which  is  made  up  of  petals,  united  or  dis- 
tinct, is  usually  brightly  coloured,  and  acts  as  an 
advertisement  or  allurement  to  the  insects;  it  oc- 
curs chiefly  in  insect-fertilised  flowers,  and  gener- 
ally implies  the  presence  of  honey.  The  calyx  or 
outer  cup,  which  is  made  up  of  sepals,  distinct  or 
united,  acts  mainly  as  a  protective  covering. 
Plants  can  fertilise  themselves  if  necessary,  but 
in  all  the  highest  and  most  successful  plants  some 
form  or  other  of  cross-fertilisation  has  become 
almost  universal.  Self-fertilisation  goes  down  the 
hill ;  cross-fertilisation  is  the  road  to  success  and 
vigour. 


CHAPTER   VII. 

VARIOUS    MARRIAGE    CUSTOMS. 

The  simplest  and  earliest  flowering  plants 
had  probably  only  three  sets  of  organs — leaves, 
stamens,  and  pistils — workers,  males,  and  females. 
Their  flowers  consisted  at  best  of  the  necessary 
organs,  enclosed,  perhaps,  in  a  few  protective 
sheathing  leaves,  rather  smaller  than  the  rest, 
the  forerunners  of  a  calyx.     How,  then,  did  mod- 


VARIOUS  MARRIAGE   CUSTOMS.  87 

ern  flowers  come  to  get  at  last  their  brilliant 
corollas  ? 

We  must  remember  that  anything  which  made 
flying  insects  visit  plants  would  be  of  use  to  the 
flowers,  as  promoting  cross-fertilisation.  Now,  as 
far  as  we  can  see  at  present,  before  flying  insects 
were  evolved  in  the  animal  world,  there  could 
have  been  no  such  things  as  bright-hued  blossoms 
in  the  vegetable  kingdom.  But  insects  must  very 
early  have  gone  about  eating  pollen  on  plants,  as 
they  do  to  this  day  in  many  instances  ;  and  though 
in  itself  this  would  be  a  loss  to  the  plant,  yet 
plants  have  often  found  it  well  worth  their  while 
to  pay  blackmail  to  insects  in  return  for  some 
benefit  incidentally  conferred  upon  them.  Again, 
as  the  insects  flew  from  plant  to  plant,  they  would 
be  sure  to  carry  pollen  on  their  heads  and  legs ; 
and  they  would  rub  off  this  pollen  on  the  sticky 
stigma  of  the  next  flower  they  visited,  which 
would  make  them  on  the  whole  useful  and  profit- 
able visitors.  So  the  plants,  finding  the  good 
cross-fertilisation  did  them,  began  in  time  to  bribe 
the  insects  by  producing  honey  in  the  neighbour- 
hood of  their  pistils  and  stamens,  and  also  to  at- 
tract their  eyes  from  afar  by  means  of  those  allur- 
ing and  brilliantly-coloured  advertisements  which 
we  call  petals. 

I  don't  mean,  of  course,  that  the  plants  knew 
they  were  doing  all  this;  they  were  unconscious 
agents.  Whenever  any  variation  in  the  right  di- 
rection occurred  by  chance,  natural  selection  im- 
mediately favoured  it,  so  that  in  the  end  it  comes 
almost  to  the  same  thing  as  if  the  plant  deliber- 
ately intended  to  allure  the  insect ;  and  for  brev- 
ity's sake  I  shall  often  so  word  things. 

How  did  the  plant  first  come  to  develop,  such 


88  THE   STORY   OF   THE   PLANTS. 

bright-hued  petals?  I  think  in  this  way.  Most 
early  types  of  flowers  have  a  great  many  stamens 
apiece,  and  these  stamens  are  so  extremely  nu- 
merous that  one  or  two  of  them  might  readily  be 
spared  for  any  other  purpose  the  plant  found  use- 
ful. Gradually,  as  botanists  imagine,  an  outer 
row  of  these  stamens  got  flattened  out  into  a  form 
like  foliage  leaves,  only  without  any  ribs  or  veins 
to  speak  of,  and  developed  bright  colours  to  at- 
tract the  insects.  Such  a  flattened  and  gaily- 
decked  stamen,  with  no  pollen-bearing  bag,  is 
what  we  call  a  petal.  It  is  usually  expanded, 
thin,  and  spongy,  and  it  is  admirably  adapted  for 
the  display  of  bright  colours. 

We  have  still  certain  flowers  among  us  which 
show  us  pretty  clearly  how  this  change  took  place. 
The  common  white  water-lily  is  one  of  them.  In 
the  centre  of  the  blossom,  in  that  beautiful  plant, 
we  find  a  large  pistil  and  numerous  stamens  of 
the  ordinary  sort,  with  round  stalks  or  filaments, 
and  yellow  pollen-bags  hanging  out  at  their  ends. 
Then,  as  we  move  forward,  we  find  the  filaments 
or  stalks  growing  flatter  and  broader,  and  the 
pollen-bags  gradually  less  and  less  perfect.  Next 
we  come  to  a  few  very  flat  and  broad  stamens, 
looking  just  like  petals,  but  with  two  empty  pol- 
len-bags, or  sometimes  only  one,  stuck  awk- 
wardly on  their  edges.  Last  of  all  we  arrive  at 
true  petals  without  a  trace  in  any  way  of  pollen- 
bags.  I  believe  the  water-lily  preserves  for  us 
still  some  memory  of  the  plan  by  which  petals 
were  first  invented.  Such  relics  of  old  conditions 
are  common  both  in  plants  and  animals;  they 
help  us  greatly  to  reconstruct  the  history  of  the 
path  by  which  the  various  kinds  have  reached 
their  present  perfection. 


VARIOUS  MARRIAGE  CUSTOMS.        89 

Even  in  our  own  day,  in  plants  where  stamens 
are  numerous,  they  often  tend  to  develop  into 
petals,  especially  when  growing  in  very  rich  soil, 
or  under  cultivation.  This  is  what  we  call  "  doub- 
ling "  a  flower.  In  the  double  rose,  for  example, 
the  extra  petals  are  produced  from  the  stamens  of 
the  interior,  and  if  you  examine  them  closely  you 
will  see  that  they  often  show  every  possible  grada- 
tion and  intermediate  stage,  from  the  perfect  sta- 
men to  the  perfect  petal.  The  same  thing  read- 
ily happens  with  buttercups,  poppies,  and  many 
other  flowers.  We  may  take  it  for  granted,  then, 
that  petals  are,  in  essence,  a  single  outer  row  of 
stamens,  flattened  and  coloured,  and  set  apart  by 
the  plant  to  advertise  its  honey  to  insects,  and  so 
induce  them  to  visit  and  fertilise  it. 

In  the  largest  and  most  familiar  group  of  flow- 
ering plants,  to  which  almost  all  'the  best-known 
kinds  belong,  the  original  number  of  petals  seems 
to  have  been  five;  and  we  will,  take  this  number 
as  regular  for  the  present,  explaining  separately 
those  cases  where  it  is  exceeded  or  diminished. 
The  common  ancestor  of  all  these  plants,  we  may 
conclude,  had  all  its  parts  in  rows  of  five.  Thus 
it  had  five,  ten,  or  fifteen  carpels  in  its  pistil — that 
is  to  say,  one,  two,  or  three  rows  of  five  carpels 
each;  it  had  five,  ten,  or  fifteen  stamens,  it  had 
five  or  ten  petals,  and  it  had  a  calyx,  outside  all, 
of  five  sepals.  We  will  now  proceed  to  examine 
in  detail  some  of  the  many  curious  marriage  cus- 
toms which  have  arisen  among  the  group  of  plants 
that  started  with  this  ground-plan. 

One  great  family  of  plants  which  early  divided 
itself  from  this  great  central  stock  is  the  family 
of  the  buttercups.     Our  common  English  bulbous 


90  THE    STORY   OF   THE    PLANTS. 

buttercup  is  one  of  its  best-known  members.  It 
is  yellow  in  colour,  a  point  which  is  common  to 
most  early  and  simple  flowers,  because  the  sta- 
mens are  generally  yellow,  and  when  they  devel- 
oped into  petals  they  naturally  retained  at  first 
their  original  colouring.  Only  later  and  for  vari- 
ous special  reasons  did  certain  higher  flowers 
come  by  degrees  to  be  white,  pink,  red,  blue, 
purple,  or  variegated.  There  is  some  reason  to 
believe,  indeed,  that  the  various  other  colours 
were  developed  one  after  the  other  in  the  order 
here  named,  and  to  the  present  day  all  the  sim- 
plest families  of  flowers  remain  chiefly  yellow,  as 
do  the  simpler  and  earlier  members  of  more  ad- 
vanced families. 

The  common  bulbous  buttercup  is  thus  pre- 
vailingly yellow,  because  it  is  an  early  and  simple 
type  of  flower.  It  consists  of  four  distinct  and 
successive  layers,  or  whorls  of  organs.  Outside 
all  comes  a  calyx  of  five  sepals,  which  cover  the 
flower  in  the  bud,  but  are  hardly  noticeable  in  the 
open  blossom.  They  also  serve  to  keep  off  ants 
and  other  creeping  insects,  for  which  purpose  they 
are  turned  back  on  the  stem,  and  are  covered 
with  small  hairs.  "  But  I  thought  the  plant 
wanted  to  attract  insects,"  you  will  say.  Yes,  the 
right  kind  of  insects,  the  flying  types,  which  go 
from  one  flower  to  another  of  the  same  sort,  and 
so  promote  due  fertilisation.  Flying  insects,  at- 
tracted by  colour  and  shape  of  petals,  keep  to  one 
brand  of  honey  at  a  time ;  they  never  mix  their 
liquors.  But  ants  are  drawn  on  by  the  smell  of 
honey  only  ;  they  crawl  up  one  stem  after  an- 
other indiscriminately,  and  steal  the  nectar  which 
the  plant  intends  for  its  regular  winged  visitors. 
Even  if  they  do  occasionally  fertilise  a  flower,  it 


VARIOUS  MARRIAGE  CUSTOMS.        91 

will  probably  be  with  pollen  of  another  kind,  so 
that  the  result  will  be,  not  a  perfect  plant,  but  a 
miserable  hybrid,  ill  adapted  for  any  conditions. 
Hence  plants  usually  possess  advanced  devices 
for  keeping  off  ants  and  other  climbing  thieves 
from  their  precious  honey.  Hairs  on  the  stalk 
and  calyx  are  enough  to  secure  this  object  in  the 
meadow  buttercup,  which  has  a  tall  stem,  and 
therefore  is  not  so  easily  climbed  ;  for  the  hairs, 
small  as  they  look  to  us,  prove  to  the  ant  a  per- 
fect forest  of  underwood.  But  in  the  early 
bulbous  buttercup,  which  has  a  shorter  stem,  and 
the  smell  of  whose  honey  is  therefore  more  allur- 
ing to  the  groundling  ant,  this  device  is  not  alone 
sufficient ;  so  the  calyx  on  opening  turns  down  its 
separate  sepals  close  against  the  stem  in  such  a 
way  as  to  form  a  sort  of  lobster-pot,  out  of  which 
the  creeping  insect  can  never  extricate  himself. 

Inside  the  calyx-layer  of  five  sepals  comes 
next  the  corolla-layer  of  five  petals.  These  petals, 
as  we  saw,  are  the  attractive  business  advertise- 
ment of  the  flower  ;  they  contain  at  the  base  of 
each  a  tiny  honey-gland  or  nectary,  which  is  cov- 
ered by  a  scale  or  small  inner  petal,  so  to  speak, 
to  protect  it  from  the  attacks  of  thievish  insects. 
But  when  the  bee  or  other  proper  fertilising  agent 
arrives  at  the  flower,  he  lights  on  the  set  of  carpels 
in  the  very  centre  of  the  blossom,  and  proceeds  to 
go  straight  for  the  little  store  of  honey.  As  he  does 
so,  he  turns  gradually  round  all  over  the  carpels, 
and  dusts  himself  with  pollen  from  the  ripe  sta- 
mens. 

And  now  we  must  notice  another  curious 
device  for  ensuring  cross-fertilisation  in  many 
flowers.  In  the  bulbous  buttercup  the  stamens 
and  carpels  do  not  come  to   maturity  together  ; 


92  THE   STORY   OF   THE    PLANTS. 

the  Stamens  ripen  first,  and  after  them  the 
carpels.  How  does  this  ensure  cross-fertilisa- 
tion ?  Why,  if  the  bee  comes  to  a  flower  in  the 
first  or  male  stage,  in  which  the  stamens  are  at 
their  full,  and  discharging  pollen,  the  sensitive 
surfaces  or  stigmas  of  the  carpels  will  yet  be 
immature,  so  that  he  cannot  fertilise  them  with 
pollen  from  their  own  blossom.  He  can  only 
collect  there,  without  disbursing  anything.  But 
as  soon  as  he  comes  to  a  flower  in  its  second  or 
female  stage,  with  the  carpels  ripe,  and  their 
sensitive  surfaces  sticky,  he  will  rub  off  some 
of  the  pollen  he  has  thus  collected,  and  so  cross- 
fertilise  the  flower  he  is  visiting. 

Each  buttercup  thus  goes  through  two  stages. 
First,  its  stamens  ripen  from  without  inward,  till 
all  have  shed  their  pollen  and  withered.  Then 
the  carpels  ripen  in  the  same  order,  till  all  have 
been  fertilised  by  the  appropriate  insect.  Each 
carpel  here  contains  a  single  seed,  which  begins 
to  swell  as  soon  as  the  ovary  is  impregnated. 

We  may  take  it  that  some  such  flower  as  that 
of  the  bulbous  buttercup  represents  the  original 
ancestor  of  all  the  buttercup  group,  from  which 
other  kinds  have  varied  in  many  directions. 
Omitting  for  the  present  all  questions  as  to  the 
fruit  and  seed,  which  we  must  examine  at  length 
in  a  later  chapter,  I  will  now  proceed  briefly  to 
describe  a  few  of  these  variations  in  the  butter- 
cup family. 

The  true  buttercups  themselves  are  distin- 
guished from  all  other  members  of  the  group  by 
having  a  tiny  scale  over  the  nectary  or  honey- 
gland  at  the  base  of  the  petal,  or  at  least  by 
having  the  nectary  itself  as  a  visible  pit  or  small 
depression.    Almost  all  of  them  are  yellow,  though 


VARIOUS   MARRIAGE   CUSTOMS.  93 

in  Other  respects  they  differ  from  one  another,  as 
in  the  shape  of  the  leaves,  or  in  the  way  in  which 
the  sepals  are  turned  back  to  form  a  protection 
against  insects.  One  of  the  yellow  buttercups, 
too,  commonly  called  the  lesser  celandine,  has 
varied  from  the  rest  of  the  race  in  a  peculiar 
fashion  ;  for  it  has  only  three  sepals,  instead  of 
five,  according  to  the  usual  pattern ;  while,  as  if 
to  make  up  for  this  loss  in  one  part,  it  has  eight 
petals  instead  of  five  in  its  corolla.  I  merely 
mention  this  fact  to  show  how  many  small  changes 
occur  in  different  flowers,  even  within  the  limits 
of  the  same  family.  And  though  most  of  the 
true  buttercups  are  yellow,  a  few  are  white,  such 
as  our  own  water-crowfoot,  and  the  alpine  butter- 
cup called  bachelors'  buttons;  while  still  fewer 
are  red,  like  the  turban  ranunculus  of  our  spring 
gardens. 

But  besides  the  true  buttercups,  we  have  also 
a  vast  group  of  buttercup-like  plants,  descend- 
ants of  the  same  primitive  five-petalled  ances- 
tor, and  regarded  as  members  of  the  buttercup 
order.  In  these  we  can  trace  some  curious  gra- 
dations. The  little  winter  aconite  of  our  gar- 
dens has  this  peculiarity :  the  petal  and  nectary 
have  grown  into  a  sort  of  tubular  honeycup,  much 
more  attractive  to  greedy  insects  than  the  simple 
scale-bearing  petal  of  the  buttercups.  But  as  this 
involves  lossof  expanded  colour- surface,  the  winter 
aconite  has  made  up  for  the  deficiency  by  colour- 
ing its  calyx  a  brilliant  yellow,  so  as  to  resemble 
a  corolla.  Several  other  buttercup-like  plants 
have  even  lost  their  petals  altogether,  and  make 
coloured  sepals  do  duty  in  their  place.  The 
marsh-marigold,  for  instance,  is  one  of  these ; 
what  look  like  petals  in  it  are  really  very  brilliant 


94  THE  STORY  OF  THE   PLANTS. 

yellow  sepals.  Moreover,  as  the  marsh-marigold 
is  such  a  large  and  handsome  flower,  it  easily  at- 
tracts insects  in  early  spring  ;  and  this  has  enabled 
it  to  effect  an  economy  in  the  matter  of  its  carpels 
or  female  organs.  In  the  buttercups,  we  saw, 
these  were  very  numerous,  and  each  contained 
only  one  seed ;  in  the  marsh-marigold,  on  the 
other  hand,  they  are  reduced  to  five  or  ten,  but 
each  contains  a  large  number  of  seeds.  This 
arrangement  enables  a  few  acts  of  fertilisation 
to  suffice  for  the  whole  flower.  You  will  there- 
fore find  as  a  rule  that  advanced  types  of  flowers 
have  very  few  carpels — sometimes  only  one — and 
that  when  they  are  more  numerous  they  are  often 
combined  into  a  single  ovary,  with  one  sensitive 
surface,  so  that  one  fertilisation  is  enough  for  the 
whole  of  them. 

Three  familiar  but  highly-advanced  members 
of  the  buttercup  group  will  serve  to  show  the  im- 
mense changes  effected  in  this  respect  by  special 
insect  fertilisation.  They  are  the  columbine,  the 
larkspur,  and  the  monkshood.  In  the  simple  but- 
tercups, the  honey,  we  saw,  was  easily  acces- 
sible to  many  small  insects;  but  in  the  winter 
aconite  it  was  made  more  secure  by  being  kept, 
as  it  were,  in  a  sort  of  deep  jar  ;  and  in  these  high- 
est of  the  family  it  is  still  further  hidden  away,  in 
special  nooks  and  recesses,  like  vases  or  pitchers, 
so  as  to  be  only  procurable  by  bees  and  butter- 
flies. These  higher  insects,  on  the  other  hand, 
are  the  safest  fertilisers,  because  they  have  legs 
and  a  proboscis  exactly  adapted  to  the  work  they 
are  meant  for;  and  they  have  also  as  a  rule  a 
taste  for  red,  blue,  and  purple  flowers,  rather 
than  for  simple  white  or  yellow  ones.  Hence 
the   blossoms  that  specially  lay   themselves  out 


VARIOUS   MARRIAGE   CUSTOMS.  95 

for  the  higher  insects  are  almost  always  blue  or 
purple. 

Columbine  still  retains  the  original  five  sepals 
and  five  petals  of  its  buttercup  ancestor.  But  the 
sepals  here  are  blue  or  purple,  and  are  displayed 
between  the  petals  in  a  most  curious  manner,  so 
as  to  help  in  the  coloured  advertisement  of  the 
honey.  The  petals,  on  the  other  hand,  are  turned 
into  long  spurred  horns,  each  with  a  big  drop  of 
honey  in  its  furthest  recess,  securely  placed  where 
only  an  insect  with  a  very  long  proboscis  has  any 
chance  of  reaching  it.  Within  these  two  rows 
come  the  numerous  stamens;  and  within  them 
again  a  set  of  five  carpels,  each  many-seeded. 
The  columbine  is  so  secure  of  getting  its  seed  set 
by  bees  or  butterflies  that  it  is  able  to  dispense 
with  the  extra  carpels. 

Larkspur  carries  the  same  devices  one  step 
further.  Here,  there  are  five  sepals,  coloured  blue, 
and  prolonged  into  a  spur  at  the  base,  which  cov- 
ers the  nectaries.  Why  this  outer  covering  ?  Well, 
in  columbine,  thievish  insects  like  wasps  often  eat 
through  the  base  of  the  spurred  sepals  and  steal 
the  honey,  without  benefiting  the  plant  in  any  way, 
as  they  don't  come  near  the  stamens  and  carpels. 
Larkspur  provides  against  that  evil  chance  by 
covering  its  honey  with  two  protective  coats  ;  for 
within  the  spur  of  the  sepals  lies  a  spurred  nectary 
made  up  of  the  petals.  The  petals  themselves  are 
reduced  to  two,  because  the  sepals  are  coloured, 
and  do  all  the  attractive  duty;  and  besides,  even 
these  two  petals  are  combined  into  one,  as  a  fur- 
ther economy.  But  the  arrangement  of  the  flower 
is  so  admirable  for  ensuring  fertilisation  that  the 
plant  is  able  still  further  to  dispense  with  unneces- 
sary parts ;  so  many  larkspurs  have  only  a  single 


96        THE  STORY  OF  THE  PLANTS. 

many-seeded  carpel.  Such  reductions  in  the  num- 
bers of  parts  are  always  a  sign  of  high  develop- 
ment. Where  the  devices  for  effecting  the  work 
are  poor,  many  servants  are  necessary;  where 
labour-saving  improvements  have  been  largely  in- 
troduced, a  very  few  will  do  the  same  work,  and 
do  it  better. 

Monkshood,  again,  is  another  example  of  the 
same  tendency.  Here,  the  one-sidedness  which 
we  saw  in  the  larkspur  reaches  a  still  more  ad- 
vanced development.  The  upper  sepal  is  formed 
into  a  brilliant  blue  hood,  and  it  covers  tw^o  curi- 
ously shaped  petals,  which  contain  an  abundant 
store  of  honey.  This  arrangement  is  so  splendid 
for  fertilisation  that  the  plant  is  able  largely  to 
reduce  its  number  of  stamens;  and  though  it  has 
three  carpels,  these  are  combined  at  the  base, 
thus  showing  the  first  step  towards  a  united  ovary. 

I  have  treated  the  single  family  of  the  butter- 
cups at  some  length,  because  I  wished  to  show 
you  what  sort  of  variations  on  a  single  plan  were 
common  in  nature.  We  see  here  a  family,  built 
all  on  one  scheme,  but  altering  its  architecture 
and  decoration  in  the  most  singular  degree  in  its 
different  members.  The  simplest  kinds  are  cir- 
cular, symmetrical,  orderly,  and  yellow  ;  the  high- 
est are  irregular,  somewhat  strangely  shaped,  and 
blue  or  purple.  This  is  the  general  line  of  evolu- 
tion in  flowers.  They  begin  like  the  buttercup  ; 
they  end  like  the  monkshood. 

Familiar  instances  of  round  or  radial  flowers, 
consisting  of  separate  petals,  are  the  dog-rose,  the 
poppy,  the  mallow,  and  the  herb-Robert  or  wild 
geranium.  Most  of  these  have  five  sepals  and 
five  petals;  but  in  the  poppy  the  petals  are  usual- 


VARIOUS   MARRIAGE   CUSTOMS.  97 

ly  reduced  to  four,  and  the  sepals  to  two.  Again, 
a  good  instance  of  flowers  with  separate  petals 
which  have  become  one-sided  or  irregular,  instead 
of  circularly  symmetrical,  is  afforded  us  by  the 
peaflowers,  which  include  the  pea,  the  bean,  the 
sweet-pea,  the  laburnum,  the  broom,  the  gorse, 
the  vetch,  and  the  lupine.  This  familiar  family, 
known  to  botanists  as  the  papilionaceous  or  but- 
terfly-like order  (I  trouble  you  with  as  few  long 
names  as  I  can,  so  you  must  forgive  one  or  two 
occasionally),  is  one  of  the  largest  in  the  world, 
and  includes  a  vast  number  of  the  most  useful 
and  also  of  the  most  ornamental  species.  The 
structure  of  the  flower,  which  is  very  similar  in 
them  all,  can  be  easily  studied  in  the  broom  or 
the  sweet-pea,  plants  procurable  by  everybody. 
There  are  still  five  petals,  though  two  of  them  are 
united  to  form  a  lower  portion  of  the  flower, 
known  as  the  keel ;  then  two  others  at  the  side 
are  called  the  wings;  while  a  broad  and  often 
handsomely  coloured  advertisement-petal  at  the 
top  of  all  is  called  the  standard.  The  sepals  are 
often  combined  into  a  single  calyx-piece,  though 
as  a  rule  the  calyx  still  retains  five  lobes  or  teeth, 
a  reminiscence  of  the  time  when  it  consisted  of 
five  distinct  and  separate  sepals.  The  stamens 
are  welded  together  into  a  sort  of  long  tube;  and 
the  pistil  is  reduced  to  a  single  carpel  or  pod, 
containing  a  few  big  seeds,  very  familiar  to  most 
of  us  in  the  case  of  the  pea,  the  bean,  and  the 
scarlet-runner.  This  shape  of  flower  has  proved 
so  successful  in  the  struggle  for  life  that  papil- 
ionaceous plants  are  now  common  everywhere, 
while  hundreds  of  different  kinds  are  known  in 
various  countries. 

Yet   closely  as   the  peaflowers  resemble  one 
7 


pS  THE   STORY   OF  THE    PLANTS. 

another  in  general  aspect,  they  have  still  among 
themselves  a  curious  variety  of  marriage  customs. 
I  will  mention  two  only.  In  gorse,  a  flower  which 
everybody  can  easily  examine,  the  wings  have 
two  little  knobs  at  the  sides  for  the  bee  to  alight 
upon.  As  he  does  so,  the  corolla  springs  open 
elastically,  and  dusts  him  all  over  with  the  fer- 
tilising pollen.  But  once  it  has  burst,  it  remains 
permanently  open,  the  keel  hanging  down  in  a 
woe-begone  way,  so  that  no  bee  troubles  himself 
again  to  visit  it.  This  saves  time  for  the  bees, 
and  enables  them  quicker  to  fertilise  the  remain- 
ing flowxrs;  for  when  they  see  a  gorse-blossom 
"  sprung,"  as  we  call  it,  they  recognise  at  once 
that  it  has  already  been  fertilised,  and  they  know 
they  can  get  no  food  by  going  there.  In  the 
lupine,  on  the  other  hand,  and  in  the  common 
little  English  birdsfoot-trefoil,  the  keel  is  sharp 
at  the  point,  and  the  pollen  is  shed  into  it  before 
the  flower  fully  opens.  When  a  bee  lights  on  the 
knobs  at  the  side,  he  depresses  the  keel,  and  the 
pollen  is  pumped  out  against  his  breast  in  the 
most  beautiful  manner.  I  hope  my  readers  will 
try  some  of  these  experiments  in  summer  for 
themselves,  and  satisfy  their  own  minds  whether 
these  things  are  so. 

So  far,  we  have  dealt  mainly  with  flowers  in 
which  the  petals  are  all  still  distinct  and  separate. 
But  in  a  great  many  plants,  the  petals  have  grown 
together,  so  as  to  form  a  single  piece,  a  ''tubular 
corolla,"  as  we  call  it.  This  arrangement  is  very 
well  seen  in  the  harebell,  the  Canterbury  bell,  the 
heath,  and  the  convolvulus.  How  did  such  an 
arrangement  arise  ?  Well,  in  many  flowers  even 
with  distinct  petals  there  is  a  slight  tendency  for 


VARIOUS   MARRIAGE   CUSTOMS.  99 

adjacent  parts  to  adhere  at  the  base ;  and  in  cer- 
tain blossoms  this  tendency  to  adhesion  must 
have  benefited  the  plant,  because  it  would  allow 
the  proper  fertilising  insect  to  get  in  with  ease, 
and  to  find  his  way  at  once  to  the  stamens  and 
stigma  or  sensitive  surface.  The  consequence  is 
that  the  majority  of  the  higher  plants  have  now 
corollas  in  a  single  piece;  and  most  of  these  are 
also  coloured  red,  blue,  or  purple.  Still,  even 
now  many  of  them  retain  marks  of  the  original 
five  petals.  For  instance,  the  harebell  has  the 
edge  of  the  corolla  vandyked  into  five  marked 
lobes;  while  in  the  primrose,  only  the  base  of  the 
corolla  forms  a  tube  or  united  pipe,  the  outer 
part  being  composed  of  five  deeply-cut  lobes, 
reminiscences  of  the  five  original  petals.  Indeed, 
some  relations  of  the  primrose,  such  as  the  pim- 
pernel and  the  woodland  loose-strife,  have  the 
petals  only  slightly  united  at  the  base,  and  would 
hardly  be  noticed  by  a  casual  observer  as  possess- 
ing a  tubular  corolla. 

There  is  one  marriage  custom  of  the  primrose, 
however,  so  very  interesting  that  we  must  not 
pass  it  by  even  in  so  brief  a  survey.  Most  chil- 
dren are  aware  that  we  have  in  our  woods  two 
kinds  of  primroses,  which  they  know  respectively 
as  pin-eyed  and  thrum-eyed.  In  the  pin-eyed 
form  (Fig.  18),  only  the  little  round  stigma  is 
visible  at  the  top  of  the  pipe,  while  the  stamens, 
here  joined  with  the  corolla-tube,  hang  out  like 
little  bags  half-way  down  the  neck  of  it.  In  the 
thrum-eyed  form  (Fig.  19),  on  the  other  hand, 
only  the  stamens  are  visible  at  the  top  of  the 
tube,  while  the  stigma,  erected  on  a  much  shorter 
style,  occupies  just  the  same  place  in  the  tube 
that  the  stamens  occupied  in  the  sister  blossom. 


lOO 


THE  STORY  OF  THE   PLANTS. 


Now,  each  primrose  plant  bears  only  one  form  of 
flower.  Therefore,  if  a  bee  begins  visiting  a 
thrum-eyed  form,  he  will  collect  pollen  on  his 
proboscis  at  the  very  base  only ;  and  as  long  ar 
he  goes  on  visiting  thrum-eyed  flowers,  he  can 
only  collect,  without  getting  rid  of  any  grains  on 


Fig.  i8. — Pin-eyed  primrose, 
cut  open  so  as  to  show  the 
arrangement  of  the  stamens 
and  stigma. 


Fig.  19. — Thrum-eyed  prim- 
rose, cut  open  so  as  to 
show  stamens  and  stigma. 


the  deep-set  stigmas.  But  when  he  flies  away  to 
a  pin-eyed  blossom,  the  part  of  his  proboscis 
which  collected  pollen  before  will  now  be  op- 
posite the  stigma,  and  will  fertilise  it ;  while 
at  the  same  time  he  will  be  gathering  fresh 
pollen  below,  to  be  rubbed  off  on  the  sensitive 
surface   of  a  short-styled  flower  in  due   season. 


VARIOUS   MARRIAGE   CUSTOMS.  lOI 

Thus  every  pin-eyed  blossom  must  always  be  fer- 
tilised by  a  thrum-eyed,  and  every  thrum-eyed  by 
a  pin-eyed  neighbour.  This  is  one  of  the  most 
ingenious  arrangements  known  for  cross-fertilisa- 
tion. 

Much  as  I  should  like  to  dwell  further  on 
these  interesting  cases,  I  must  hurry  on  to  com- 
plete our  rapid  survey  of  a  great  subject.  Flow- 
ers like  the  harebell  and  the  primrose  are  tubular 
but  regular.  Other  flowers  with  a  tubular  corolla 
go  yet  a  step  further  and  are  irregular  also.  This 
irregularity,  like  that  of  the  monkshood,  secures 
for  them  in  the  end  greater  certanity  of  fertilisa- 
tion. Two  well-known  groups  of  this  sort  are 
the  sages,  on  the  one  hand,  and  the  fox-gloves, 
monkey-plants,  and  snap-dragons  on  the  other. 
I  shall  mention  only  one  instance  of  special  de- 
vices for  cross-fertilisation  in  these  groups,  that 
of  the  various  sages,  beautifully  seen  in  the  large 
blue  salvias  of  our  gardens.  In  this  plant  there 
are  only  two  stamens,  though  most  of  the  group 
to  which  it  belongs,  have  four,  because  the  ex- 
cellent arrangements  for  fertilisation  make  this 
single  pair  a  great  deal  more  effective  than  the 
thirty  or  forty  required  by  the  common  buttercup. 
For  the  stamens  are  delicately  poised  on  a  sort 
of  lever,  so  that  the  moment  the  bee  enters  the 
flower,  they  descend  and  embrace  him,  as  if  by 
magic.  While  the  stamens  alone  are  ripe,  this 
continues  to  happen  with  each  flower  he  visits; 
but  when  he  goes  away  to  an  older  blossom,  he 
finds  the  stigma  ripe,  and  bending  over  into  the 
spot  previously  occupied  by  the  stamens.  You 
can  try  this  experiment  very  easily  for  yourself 
by  putting  a  straw  or   bent   of  grass  down   the 


I02  THE   STORY   OF   THE   PLANTS. 

tube  of  a  garden  salvia,  when  the  stamens  will  at 
once  bend  down  and  embrace  it  in  the  way  I  have 
mentioned. 

You  must  not  suppose,  however,  that  all  flow- 
ers are  fertilised  by  bees  and  butterflies.  Many 
plants  lay  themselves  out  for  quite  different  vis- 
itors. Take  for  example  our  common  English 
figwort.  This  is  a  curious,  lurid-looking,  reddish- 
brown  blossom,  shaped  somewhat  like  a  helmet, 
and  it  is  fertilised  almost  exclusively  by  wasps. 
Its  shape  and  size  exactly  adapt  it  for  a  wasp's 
head;  and  it  blooms  at  the  time  of  year  when 
wasps  are  numerous.  Now  wasps,  as  you  know, 
are  carnivorous  and  omnivorous  creatures  ;  so  the 
figwort,  to  attract  them,  looks  as  meaty  as  it  can, 
and  has  an  odour  not  unlike  that  of  decaying 
mutton.  Certain  tropical  flowers  again  attract 
carrion-flies,  and  these  have  big  blossoms  that 
look  like  decomposing  meat,  and  smell  disgust- 
ingly. A  South  African  flower  of  this  sort,  the 
Stapelia,  is  sometimes  cultivated  as  a  curiosity  in 
greenhouses.  I  have  already  remarked  on  the 
white  flowers  which  open  at  night,  and  attract  the 
moths  of  twilight ;  while  others  again  lay  them- 
selves out  to  be  fertilised  by  midges,  beetles,  and 
other  insect  riff-raff.  Most  of  these  have  the 
honey  displayed  on  wide  open  discs,  where  it  can 
be  sipped  by  insects  with  hardly  any  proboscis. 

In  our  latitudes  it  is  only  insects  that  so  act 
as  fertilisers ;  but  in  the  tropics  the  work  of  fer- 
tilisation is  often  performed  by  birds,  such  as 
humming-birds,  sun-birds,  and  brush-tongued 
lories.  Many  of  the  most  brilliant  and  beautiful 
among  the  bell-shaped  tropical  flowers  have  been 
specially  developed   to  suit  the  tastes  and  habits 


VARIOUS   MARRIAGE   CUSTOMS.  1 03 

of  these  comparatively  large  and  powerful  ferti- 
lisers. The  tongues  of  all,  but  especially  of  the 
humming-birds,  are  admirably  adapted  for  suck- 
ing honey  from  flowers,  as  they  are  long  and 
tubular,  sometimes  forked  at  the  tip,  and  often 
hairy  so  as  to  lick  up  both  honey  and  insects. 
The  length  of  the  beak  and  tongue  varies  to  a 
great  extent  in  accordance  with  the  depth  of  the 
tube  in  the  flowers  they  fertilise.  Bird  and  flower, 
in  other  words,  have  each  been  developed  to  suit 
one  another.  The  same  sort  of  correspondence 
may  often  be  observed  between  insects  and  flowers 
developed  side  by  side  for  mutual  convenience. 

One  more  point  I  should  like  to  touch  upon 
before  I  pass  away  from  this  part  of  the  subject; 
and  that  is  the  lines  or  spots  so  often  found  on 
the  petals  of  highly  developed  flowers.  These  for 
the  most  part  act  as  honey-guides,  to  lead  the  bee 
or  other  fertilising  insect  direct  to  the  nectar.  A 
very  good  case  of  this  may  be  seen  in  an  Indian 
plant  which  is  found  in  every  English  cottage 
garden — that  is  to  say  the  so-called  nasturtium. 
This  blossom  can  only  be  fertilised  by  humble-bees 
and  humming-bird  hawk-moths,  no  other  insect  in 
England  at  least  having  a  proboscis  long  enough 
to  reach  the  bottom  of  the  very  deep  spur  which 
holds  the  honey.  Now,  humming-bird  hawk- 
moths  do  not  light  on  a  flower,  but  hover  lightly 
poised  on  their  quivering  wings  in  front  of  it.  So 
all  the  arrangements  of  the  flower  are  strictly  set 
forth  in  accordance  with  the  insect's  habit.  The 
calyx  consists  of  five  sepals  with  a  very  long  spur, 
the  end  of  which,  as  you  can  find  out  by  biting  it, 
is  full  of  honey.  Then  come  five  petals,  not,  how- 
ever, all  alike,  but  divided  into  two  distinct   sets, 


I04  THE  STORY  OF  THE   PLANTS. 

an  upper  pair  and  a  lower  triplet.  The  upper  pair 
are  broad  and  deeply-lined  with  dark  veins,  which 
all  converge  about  the  mouth  of  the  spur,  and  so 
show  the  inquiring  insect  exactly  where  to  go  in 
search  of  honey.  The  lower  three,  on  the  other 
hand,  have  no  lines  or  marks,  but  possess  a  curi- 
ous sort  of  fence  running  right  across  their  face, 
intended  to  prevent  other  flying  insects  from 
alighting  and  rifling  the  flower  without  fertilising 
the  ovary.  This  flower,  too,  has  two  successive 
stages  ;  it  opens  male,  with  stamens  only,  which 
bend  upward  towards  the  insect ;  later,  it  becomes 
female,  the  stigma  opens  and  becomes  forked,  and 
bends  down  so  as  to  occupy  the  very  same  place 
previously  occupied  by  the  ripe  stamens. 

A  great  many  well-known  flowers  have  such 
lines  as  honey-guides.  If  I  have  succeeded  so  far 
in  interesting  you  in  the  subject,  you  will  find  it  a 
pleasant  task  to  hunt  them  out  for  yourself  in  the 
violet,  the  scarlet  geranium,  the  spotted  orchid, 
and  the  tiger  lily. 

So  far  I  have  dealt  only  with  the  marriage  ar- 
rangements of  those  plants  which  are  fertilised  by 
insects  or  birds,  and  which  belong  to  the  great 
group  of  flowering  plants  descended  from  an  early 
common  ancestor  with  five  petals.  We  must  next 
deal  briefly  with  the  marriage  customs  of  the  in- 
sect-fertilised class  among  the  other  great  group 
whose  ancestor  started  with  but  three  petals  ;  and 
after  that  we  must  go  on  to  the  other  mode  of 
fertilisation  by  means  of  the  wind  or  of  self-im- 
pregnation. 

This  chapter  has  consisted  so  much  of  special 
cases  that  I  do  not  think  it  stands  in  the  same 
need  of  a  summary  as  all  its  predecessors. 


MORE   MARRIAGE   CUSTOMS.  105 

CHAPTER   VIII. 

MORE    MARRIAGE    CUSTOMS. 

Almost  all  the  flowering  plants  with  which 
most  people  are  familiar — all,  indeed,  save  the 
pines  and  other  conifers — belong  to  one  or  other 
of  two  great  groups  or  alliances,  each  remotely 
descended  from  a  common  ancestor.  The  flow- 
ers we  have  hitherto  been  considering  are  entirely 
those  which  belong  to  one  of  these  two  groups — 
the  group  which  started  with  rows  of  five,  having 
five  sepals,  five  petals,  five  or  ten  stamens,  and 
five  or  ten  carpels.  In  several  cases,  certain  of 
these  rows  have  been  simplified  or  reduced  in 
number;  but  almost  always  we  can  see  to  the 
end  some  trace  of  the  original  fivefold  arrange- 
ment. This  fivefold  arrangement  is  very  con- 
spicuous in  all  the  stonecrops,  and  it  may  also  be 
well  noticed  in  wild  geraniums,  and  less  well  in 
the  strawberry,  the  dog-rose,  and  the  cinquefoil. 

In  the  present  chapter,  however,  I  propose  to 
go  on  to  sundry  flowers  of  the  other  great  group 
which  has  its  parts  in  rows  of  three,  and  to  show 
how  they  have  been  affected  by  insect  visits. 
This  will  give  us  a  clearer  view  of  the  whole 
subject,  while  it  will  also  form  a  general  intro- 
duction to  systematic  botany  for  those  of  my 
readers  who  may  be  induced  by  this  book  to 
carry  their  studies  in  this  direction  further. 

Before  proceeding,  however,  there  is  one  little 
point  I  should  like  to  note  about  the  fivefold 
flowers,  which  we  shall  find  much  more  common 
in  the  threefold,  and  among  the  wind-fertilised 
species.     This  is  the  separation   of  the  sexes  in 


Io6  THE   STORY   OF   THE   PLANTS. 

different  blossoms  or  even  on  separate  plants. 
All  the  flowers  we  have  so  far  considered  have 
contained  both  male  and  female  portions — have 
been  made  up  of  stamens  and  carpels  united  to- 
gether in  the  self-same  blossom.  But  many  of 
them,  as  you  will  recollect,  have  not  been  actively 
both  male  and  female  at  the  same  moment.  The 
stamens  ripened  first,  the  sensitive  surface  of  the 
carpels  afterwards  ;  and  this,  as  we  saw,  tended 
to  promote  cross-fertilisation.  But  if  in  any  spe- 
cies all  the  stamens  in  certain  flowers  were  to  be 
suppressed  or  undeveloped,  while  in  other  flowers 
the  same  thing  happened  to  the  carpels,  self- 
fertilisation  would  become  an  absolute  impossi- 
bility, and  every  blossom  would  necessarily  be 
impregnated  from  the  pollen  of  a  neighbour. 
Natural  selection  has  accordingly  favoured  such 
an  arrangement  in  a  considerable  number  of  the 
higher  plants.  In  such  cases  some  of  the  flowers 
consist  of  stamens  only,  with  no  carpels;  while 
others  consist  of  carpels  alone,  with  no  stamens. 
But  as  all  are  descended  from  ancestors  which 
had  both  organs  combined  in  the  same  flower, 
remnants  of  the  stamens  often  exist  in  the  female 
flowers  as  naked  filaments  or  barren  threads, 
while  remnants  of  the  carpels  equally  exist  in  the 
male  flowers  as  central  knobs  without  seeds  or 
ovules. 

The  beautiful  begonias,  so  much  cultivated  in 
conservatories,  give  us  an  excellent  example  of 
such  single-sex  flowers.  In  these  plants  the  males 
and  females  are  extremely  different.  The  male 
flower  has  four  coloured  and  petal-like  sepals, 
surrounding  a  number  of  central  stamens.  The 
female  flower  has  five  coloured  and  petal-like 
sepals,  surrounding  a  group   of   daintily-twisted 


MORE   MARRIAGE   CUSTOMS.  1 07 

central  stigmas,  while  at  the  base  of  the  blossom 
is  a  large  triangular  ovary,  containing  the  young 
seeds  or  ovules.  Usually  the  flowers  grow  in 
little  bunches  of  three,  each  bunch  consisting  of 
two  males  and  one  female. 

In  the  pumpkins,  cucumbers,  and  melons, 
separate  male  and  female  flowers  also  exist  on 
the  same  plant.  The  females  here  may  be  easily 
recognised  by  having  an  ovary  or  small  unde- 
veloped fruit  at  the  back  of  the  blossom,  which 
you  can  cut  across  so  as  to  show  the  young  seeds 
or  ovules  within  it.  As  the  proper  insects  for  fer- 
tilising cucumbers  and  melons  do  not  live  in  Eng- 
land, gardeners  usually  impregnate  the  female 
flowers  by  bringing  pollen  from  the  males  to 
them  with  a  camel's-hair  brush.  This  process  is 
commonly  known  as  "  setting  "  the  melons.  Many 
other  garden  flowers  have  separate  male  and  fe- 
male blossoms,  which  the  beginner  can  easily  rec- 
ognise for  himself  if  he  takes  the  trouble  to  look 
for  them. 

'In  the  instances  we  have  hitherto  considered, 
the  male  and  female  blossoms  live  on  the  same 
plant.  But  the  best  cross-fertilisation  of  all  is 
that  which  is  secured  where  the  fathers  and 
mothers  belong  to  totally  distinct  plants,  a  plan 
for  facilitating  which  we  have  already  seen  in  the 
common  primrose.  Well,  now,  if  any  species  took 
to  producing  all  male  flowers  on  one  plant,  and 
all  females  on  another,  this  great  end  would  be- 
come absolutely  certain,  for  every  blossom  would 
then  always  be  fertilised  by  the  pollen  brought 
from  a  distinct  plant.  Many  such  instances  have 
accordingly  been  produced  in  the  world  around 
us  by  natural  selection.  Only,  the  two  kinds  of 
plants  must  always  grow  in  one  another's  neigh- 


io8 


THE  STORY  OF  THE   PLANTS. 


bourhood.  Hemp,  for  example,  is  a  case  of  a 
plant  where  such  an  arrangement  already  exists; 
some  plants  are  male  only,  while  some  are  female. 
Mistletoe  and  hops  are  other  well-known  in- 
stances, which  the  reader  should  carefully  ex- 
amine for  himself  at  the  proper  season. 

All  these  are  fivefold  flowers,  and  I  have 
brought  them  in  here  merely  because  one  of  the 
earliest  and  simplest  threefold  flowers  we  are 
going  to  consider  has  also  this  peculiarity  of 
separate  sexes.  This  is  the  common  arrowhead, 
a  plant  that  grows  in  watery  ditches,  and  a  capi- 


FiG.  20. — I,  male,  and  II,  female  flowers  of  arrowhead. 


tal  example  of  the  threefold  type  in  its  simpler 
development.  Each  flower,  whether  male  or  fe- 
male, has  a  green  calyx  of  three  small  sepals,  and 
a  white  corolla  of  three  much  larger  and  some- 
what papery  petals  (Fig.  20).  But  the  male 
flowers  have  in  their  centre  an  indefinite  number 
of  clustering  stamens  ;  while  the  female  flowers 
have  an  equally  numerous  set  of  tiny  carpels. 
The  blossoms  grow  in  whorls  on  the  same  stem, 
the  males  above,  the  females  beneath  them.  At 
first  sight  you  would  think  this  a  bad  arrange- 
ment, because  you  might  fancy  pollen  from  the 


MORE   MARRIAGE   CUSTOMS. 


109 


males  would  certainly  fall  or  blow  out  upon  the 
females  beneath  them.  But  the  plant  prevents 
that  catastrophe  by  a  very  simple  dodge,  which 
we  shall  have  occasion  to  notice  in  many  other 
parallel  cases.  The  flowers  open  from  below  up- 
ward ;  thus  the  females  mature  first,  and  are  fer- 
tilised by  insects  which  bring  to  them  pollen  from 
other  plants  already  rifled  ;  later  on  the  males 
follow  suit,  and  their  pollen  is  carried  off  by  the 
visiting  insect  to  the  female  flowers  on  the  next 
plant  it  visits.  Indeed,  you  may  gather  by  this 
time  how  great  a  variety  of  devices  natural  selec- 
tion has  produced  for  securing  this  great  deside- 
ratum of  fresh  blood,  or  cross-fertilisation,  from  a 
totally  distinct  plant  colony. 

A  much  commoner  English  wild-flower  than 
the  arrowhead  shows  us  another  form  of  early 
threefold  blossom.  I  mean  the  water-plantain 
(Fig.  21),  a  pretty  feath- 
ery weed,  which  grows  by 
the  side  of  most  ponds 
and  lakelets.  In  the  wa- 
ter-plantain you  have  a 
flower  of  both  sexes  com- 
bined; it  consists  of  three 
green  sepals,  forming  a 
protective  calyx ;  three 
delicate  pinky-white  pet- 
als, forming  the  corolla; 
six  stamens — that  is  to 
say,  two  rows  of  three 
each ;  and  a  number  of 
small  one-seeded  carpels, 

exactly  as  in  the  buttercup,  which  occupies,  in 
fact,  the  corresponding  place  among  the  fivefold 
flowers. 


Fig.  21. — Flower  of  water- 
plantain.  The  male  and  fe- 
male parts  are  in  the  same 
blossom. 


no  THE   STORY   OF   THE   PLANTS. 

But  it  is  not  often  in  the  threefold  flowers  that 
we  get  the  calyx  green  and  the  corolla  coloured, 
as  in  these  simple  and  very  early  types.  Most 
often  in  this  great  group  of  plants  the  calyx  and 
corolla  are  both  brightly  coloured,  and  both  alike 
employed  as  effective  advertisements.  A  good 
case  of  this  sort  is  shown  in  the  flowering-rush, 
a  close  relation  of  the  arrowhead  and  the  water- 
plantain,  but  a  more  advanced  and  developed 
plant  than  either  of  them.  Here  the  calyx  and 
corolla,  instead  of  forming  two  separate  rows, 
are  telescoped  into  one,  as  it  were,  and  are  both 
rose-coloured.  In  such  cases  we  speak  of  the 
combined  calyx  and  corolla  as  \.\\^ perianth  (another 
long  word,  with  which  I'm  sorry  to  trouble  you). 
In  such  perianths,  however,  even  when  all  the 
pieces  are  of  the  same  size  and  are  similarly  col- 
oured, you  can  see  if  you  look  close  that  three  of 
them  are  outside  and  alternate  with  the  others ; 
and  these  three  are  really  the  calyx  in  disguise, 
got  up  as  a  corolla.  (An  excellent  example  of  this 
arrangement  is  afforded  by  the  common  garden 
tulip.)  Inside  its  six  rose-coloured  perianth-pieces, 
the  flowering-rush  has  nine  stamens,  arranged  in 
three  rows  of  three  stamens  each.  Finally,  in  the 
centre,  it  has  six  carpels,  equally  arranged  in  two 
rows  of  three.  Here  the  threefold  architectural 
ground-plan  of  the  flower  is  very  apparent.  You 
may  say,  in  short,  that  the  original  scheme  of  the 
two  great  groups  is  something  like  this:  five 
sepals,  five  petals,  five  stamens,  five  carpels;  or 
else,  three  sepals,  three  petals,  three  stamens, 
three  carpels.  But  in  any  instance  there  may  be 
two  or  more  such  rows  of  any  organ,  especially 
of  the  stamens ;  in  any  instance  certain  parts 
may  be  reduced  in  number  or  entirely  suppressed  ; 


MORE   MARRIAGE   CUSTOMS.  iii 

and  in  any  instance  calyx  and  corolla  may  be 
coloured  alike  so  as  almost  to  resemble  a  single 
row  or  perianth. 

There  is  one  more  point  about  the  flowering- 
rush  to  which  I  would  like  to  allude  before  going 
on  to  the  other  threefold  flowers,  and  that  is  this. 
In  arrowhead  and  water-plantain  the  carpels  are 
very  numerous,  but  each  one-seeded.  In  flower- 
ing-rush, on  the  other  hand,  which  has  a  larger 
and  handsomer  blossom,  more  attractive  to  in- 
sects, they  are  reduced  to  six  ;  but  these  six  have 
many  seeds  in  each,  so  that  a  single  act  of  fertili- 
sation suffices  for  each  of  them.  You  may  re- 
member that  among  the  fivefold  flowers  we  found 
a  precisely  similar  advance  on  the  part  of  the 
marsh-marigold  above  the  bulbous  and  meadow 
buttercups.  This  sort  of  advance  is  common  in 
nature.  Where  a  flower  learns  how  to  produce 
many  seeds  in  a  carpel,  it  can  soon  dispense  with 
several  of  its  carpels,  because  a  few  now  do  well 
what  the  many  did  badly.  Furthermore,  in  higher 
plants,  there  is  a  tendency  for  these  carpels  to 
unite  so  as  to  form  what  we  call  a  compound  ovary ^ 
with  a  single  style,  when  one  act  of  fertilisation 
suffices  for  all  of  them.  Such  combinations  or 
labour-saving  arrangements  obviously  benefit 
both  the  insect  and  the  plant,  and  have  therefore 
been  doubly  favoured  by  natural  selection. 

We  see  this  advance  beautifully  illustrated  in 
the  largest  and  loveliest  family  of  the  threefold 
flowers,  the  lily  group,  which  contains  a  great 
number  of  the  handsomest  insect-fertilised  blos- 
soms, and  is  therefore  deservedly  an  immense 
favourite  in  flower-gardens.  All  the  lilies  have  a 
perianth  (or  combined  calyx  and  corolla)  of  six 
almost  similar  brilliantly-coloured  pieces  (in  which, 


112  THE   STORY   OF  THE   PLANTS. 

however,  you  can  still,  as  a  rule,  detect  the  sepals 
by  their  habit  of  overlapping  the  petals  in  the 
bud).  Then  they  have  a  set  of  six  stamens.  Inside 
that  again  they  have  a  single  ovary,  but  if  you 
cut  it  across  with  a  penknife  you  will  see  at  once 
it  contains  three  chambers,  each  as  a  rule  with 
several  seeds;  and  these  three  chambers  are  a 
memory  of  the  time  when  the  ovary  consisted  of 
three  separate  carpels.  From  their  midst  arises 
a  single  long  style;  but  you  may  observe  all  the 
same  that  it  is  made  up  of  three  original  and  dis- 
tinct styles,  because  it  divides  at  the  top  into  three 
stigmas  or  sensitive  surfaces.  This  is  the  general 
plan  of  the  lily  group  ;  but  in  certain  individual 
lilies  the  stigma  is  undivided,  and  in  others  again 
the  parts  are  increased  to  four  or  even  to  eight,  so 
as  to  obscure  the  primitive  threefold  arrange- 
ment. 

Most  of  the  large  and  handsome  lilies  culti- 
vated in  gardens  have  perianths  of  separate  pieces, 
such  as  one  knows  so  well  in  the  tiger-lily,  the 
Turk's-cap  lily,  and  the  beautiful  Japanese  lilium 
auratum.  They  have  also  abundant  honey,  stored 
in  a  deep  groove  of  the  spotted  petals,  and  they 
are  variegated  and  lined  in  such  a  way  as  to 
guide  insects  direct  to  their  store  of  nectar.  But 
the  family  has  been  so  successful  with  the  higher 
insects,  and  has  produced  such  an  extraordinary 
variety  of  very  beautiful  and  brilliant  flowers, 
that  it  is  quite  impossible  to  speak  of  them  in 
detail.  A  few  among  them,  like  our  own  wild 
hyacinth,  show  a  slight  tendency  on  the  part  of 
the  petals  and  sepals  to  unite  into  a  bell-shaped 
tube ;  still,  even  here  the  pieces  are  really  distinct 
and  separate.  But  in  the  true  garden  hyacinth 
the  pieces  unite  into  a  tubular  perianth,  like  the 


MORE   MARRIAGE   CUSTOMS.  113 

tubular  corolla  of  the  common  harebell,  except 
that  in  the  harebell  the  tube  is  formed  by  the 
union  of  the  five  petals,  while  in  the  hyacinth  it 
is  formed  by  the  similar  union  of  three  petals  and 
three  sepals.  A  still  higher  form  of  the  same 
union  is  shown  us  by  the  lily-of-the-valley,  in 
which  the  six  perianth-pieces  join  throughout  to 
form  a  very  beautiful  heather-like  cup  or  goblet. 
Other  familiar  members  of  this  great  lily  group, 
which  you  ought  to  examine  at  leisure  for  your- 
self, in  order  to  see  how  they  are  built  up,  are  as- 
paragus, Solomon's  seal,  fritillary,  tulip,  star-of- 
Bethlehem,  squill,  garlic,  onion,  tuberose,  and 
asphodel.  The  cultivated  lilies  of  one  sort  or 
another  to  be  found  in  our  gardens  may  be  num- 
bered by  hundreds. 

A  family  of  threefold  flowers  almost  as  beau- 
tiful as  the  lily  group,  and  seldom  distinguished 
from  them  save  by  botanists,  is  that  which  bears 
the  pretty  Greek  name  of  amaryllids.  The  ama- 
ryllids  are  lilies  which  differ  from  the  rest  of  their 
kind,  in  the  fact  that  the  perianth,  still  composed 
of  six  pieces,  has  grown  up  and  around  the  ovary 
so  as  to  seem  to  spring  from  above  it,  not  below 
it.  Such  flowers  are  said  to  have  "  inferior  ova- 
ries." In  other  respects  the  amaryllids  closely 
resemble  the  lilies,  having  six  coloured  perianth- 
pieces,  six  stamens,  and  an  ovary  of  three  cham- 
bers, with  one  style  in  common.  Several  of  the 
amaryllids  are  such  familiar  flowers  that  I  shall 
venture  to  describe  them  as  illustrative  examples. 

The  snowdrop  is  an  amaryllid  which  blossoms 
in  early  spring,  and  which  shows  in  a  simple  form 
the  chief  features  of  the  family.  It  has  six  pe- 
rianth-pieces, but  these  are  still  distinctly  recog- 
nisable as  calyx  and  corolla.  The  three  sepals 
8 


114  THE   STORY   OF  THE   PLANTS. 

are  large  and  pure  white,  and  they  enclose  the 
petals;  the  three  petals  are  distinctly  smaller,  and 
tipped  with  green  in  a  very  pretty  fashion.  The 
summer  snowflake,  commonly  cultivated  in  old- 
fashioned  gardens,  is  very  like  the  snowdrop,  only 
here  the  difference  between  sepals  and  petals  has 
disappeared  ;  all  six  pieces  form  one  apparent  row, 
white,  tipped  with  green,  in  a  single  perianth. 

In  the  daffodils  and  narcissuses  we  get  a  sec- 
ond group  of  amaryllids  more  advanced  and  de- 
veloped. Here  the  six  perianth-pieces  are  almost 
alike,  though  they  may  still  be  distinguished  as 
sepals  and  petals  by  a  careful  observer.  But  the 
perianth,  which  is  tubular  below,  divides  above 
into  six  lobes,  beyond  which  it  is  prolonged  again 
into  what  is  called  a  crown,  whose  real  nature  can 
only  be  understood  by  comparison  with  such  other 
flowers  as  the  campions,  where  scales  are  inserted 
on  the  tip  of  the  petals.  This  crown  is  compara- 
tively little  developed  in  the  narcissus  and  the 
jonquil ;  but  in  the  daffodil  it  has  become  by  far 
the  largest  and  most  conspicuous  part  of  the  en- 
tire flower,  so  as  completely  to  hide  the  bee  who 
visits  it.  Of  course  this  large  crown  assists  fer- 
tilisation, and  is  a  mark  of  advance  in  the  daffodil 
and  the  petticoat  narcissus.  I  hope  these  few 
remarks  will  induce  you  to  examine  many  kinds 
of  narcissus  in  detail,  in  order  to  see  of  what 
parts  they  are  compounded. 

This  seems  a  convenient  place  to  interpose  an- 
other remark  I  have  long  wanted  to  make,  name- 
ly, that  the  threefold  flowers  are  also  for  the  most 
part  distinguished  by  having  those  narrow  grass- 
like or  sword-shaped  leaves,  with  parallel  ribs  or 
veins,  about  which  I  told  you  when  we  were  deal- 
ing with  the  question  of  varieties  of  foliage.    The 


MORE   MARRIAGE   CUSTOMS.  1 15 

fivefold  flowers,  on  the  other  hand,  have  usually 
net-veined  leaves,  either  feather-ribbed  or  finger- 
ribbed.  And  at  the  risk  of  using  two  more  horrid 
long  words,  I  shall  venture  to  add  that  botanists 
usually  speak  of  the  threefold  group  as  iiionocoty- 
ledons,  and  of  the  fivefold  group  as  dicotyledons.  I 
did  not  invent  these  words,  and  I  am  sorry  to 
have  to  use  them  here ;  but  I  will  explain  what 
they  mean  when  I  come  to  deal  with  seeds  and 
seedlings.  It  is  well  at  least  to  understand  their 
use  in  case  you  come  across  them  in  your  future 
reading. 

Another  family  of  threefold  flowers,  closely 
allied  to  the  amaryllids,  is  that  of  the  irises,  many 
examples  of  which  are  familiar  in  our  flower-gar- 
dens. It  only  differs  from  the  amaryllids,  in  fact, 
in  having  the  number  of  stamens  still  further  re- 
duced to  three,  which  is  always  a  sign  of  advance, 
because  it  shows  that  the  plants  are  so  sure  of 
fertilisation  as  to  be  able  to  dispense  with  all 
unnecessary  pollen.  The  ovary  is  also  inferior, 
which  you  will  learn  in  time  to  recognise  as  a 
constant  sign  of  high  development,  because  it 
means  that  the  base  of  the  corolla  and  calyx  have 
coalesced  with  the  carpels,  and  so  ensured  greater 
certainty  of  fertilisation.  Some  simple  members 
of  the  iris  group,  like  the  crocuses,  have  mere  tu- 
bular flowers,  with  a  very  long  funnel-like  base 
to  the  corolla,  and  with  the  ovary  buried  in  the 
ground  for  greater  safety.  They  are  early  spring 
blossoms,  which  need  much  protection  against 
cold ;  therefore  they  thus  bury  their  ovaries,  and 
sheathe  their  flower-buds  in  a  papery  covering, 
composed  of  a  thin  and  leathery  leaf.  Whenever 
a  sunny  day  comes  in  winter  the  bees  venture 
out;  and  on  all  such  days,  even  though  it  freeze 


Il6       THE  STORY  OF  THE  PLANTS. 

in  the  shade,  the  crocuses  are  open  in  the  sun- 
shine to  welcome  them. 

But  other  irises  are  more  complicated,  like  the 
gladiolus,  and  still  more  the  garden  irises,  in 
which  the  difference  between  the  calyx  and  corolla 
is  carried  to  its  furthest  point  in  this  family.  The 
sepals  in  true  irises  are  large  and  brilliantly  col- 
oured ;  they  hang  over  gracefully  ;  the  petals  are 
smaller  and  erect ;  the  stigmas  are  so  expanded 
as  to  look  like  petals;  and  they  arch  over  the 
stamens  in  a  most  peculiar  manner.  If  you  watch 
a  bee  visiting  a  garden  iris,  you  will  see  for  your- 
self the  use  of  this  most  peculiar  arrangement ; 
the  bee  lights  on  the  bending  sepal,  and  inserts 
his  head  between  the  stigma  and  the  stamen  in  a 
way  which  renders  fertilisation  simply  inevitable. 
But  the  most  curious  part  of  it  all  is  that  the 
flower,  from  the  point  of  view  of  the  bee,  resem- 
bles three  distinct  and  separate  blossoms ;  he 
alights  one  after  another  on  each  bending  sepal, 
and  proceeds  to  search  for  honey  as  if  in  a  new 
flower. 

Highest  of  all  the  threefold  flowers,  and  most 
wonderful  in  their  marriage  customs,  are  the 
great  group  of  orchids,  some  of  which  grow  wild 
in  our  English  meadows,  while  others  fix  them- 
selves by  short  anchoring  roots  on  the  branches 
of  trees  in  the  tropical  forests.  Many  of  these 
last  produce  the  handsomest  and  most  extraor- 
dinary flowers  in  the  world,  and  they  are  much 
cultivated  accordingly  in  hothouses  and  con- 
servatories. It  would  be  quite  impossible  for  me 
to  give  you  any  account  of  the  infinite  devices 
invented  by  these  plants  to  secure  insect-fertilisa- 
tion ;  and  even  the  structure  of  the  flower  is  so 
extremely  complex  that  I  can  hardly  undertake 


MORE   MARRIAGE    CUSTOMS.  117 

to  describe  it  to  you  intelligibly ;  but  I  will  give 
you  such  a  brief  statement  of  its  chief  peculiari- 
ties as  will  enable  you  to  see  how  highly  it  has 
been  specialised  in  adaptation  to  insect  visits. 

The  ovary  in  orchids  is  inferior,  and  curiously 
twisted.  It  supports  six  perianth-pieces,  three 
of  which  are  sepals,  often  long  and  very  hand- 
some; while  two  are  petals,  often  arching  like  a 
hood  over  the  centre  of  the  flower.  The  third 
petal,  called   the  lip,  is  quite  different   in   shape 


Fig.  22. — Single  flower  of  orchid,  witn  ihe  perianth  cut  away.  The 
honey  is  in  the  spur,  n  ;  the  pollen-masses  are  marked  a  ;  their 
gummy  base  is  at  r ;  the  stigma  at  st. 

and  appearance  from  the  other  two,  and  usually 
hangs  down  in  a  very  conspicuous  manner.  There 
are  no  visible  stamens,  to  be  recognised  as  such  ; 
but  the  pollen  is  contained  in  a  pair  of  tiny  bags 
or  sacks,  close  to  the  stigma.  It  is  united  into 
two  sticky  club-shaped  lumps,  usually  called  the 
pollen-masses  (Fig.  22).     In  other  words,  the  or- 


ii8 


THE   STORY   OF   THE   PLANTS. 


chids  have  got  rid  of  all  their  stamens  except  one, 
and  even  that  one  has  united  with  the  stigma. 

I  will  only  describe  the  mode  of  fertilisation  of 
one  of  these  plants,  the  common  English  spotted 
orchis;  but  it  will  suffice  to  show  you  the  extreme 
ingenuity  with  which  members  of  the  family  often 
arrange  their  matrimonial  alliances.  The  spotted 
orchis  has  a  long  tube  or  spur  at  the  base  of  its 
sepals  (Fig.  22,  ;/),  and  this  spur  contains  abun- 
dant honey.  The  pollen-masses  are  neatly  lodged 
in  two  little  sacks  or  pockets  near  the  stigma,  and 
are  so  placed  that  their  lower  ends  come  against 
the  bee's  head  as  he  sucks  the  honey.  These 
lower  ends  (r)  are  gummy  or  viscid,  and  if  you 
press  a  straw  or  the  point  of  a  pencil  against  them, 
the  pollen-masses  gum  themselves  to  it  naturally, 
and  come  readily  out  of  their  sacks  as  you  with- 
draw the  pencil  (Fig.  23).     In  the  same  way,  when 


t  IG.  23. — Pollen-masses  of  an  orchid,  withdrawn  on  a  pencil.  In 
I,  they  have  just  been  removed.  In  II,  they  have  dried  and 
moved  forward. 


the  bee  presses  them  with  his  head,  the  pollen- 
masses  stick  to  it,  and  he  carries  them  away  with 
him  as  he 'leaves  the  flower.  Just  at  first,  the 
pollen-masses  stand  erect  on  his  forehead  ;  but  as 
he  flies  through  the  air,  they  dry  and  contract,  so 
that  they  come  to   incline  forward  and  outward. 


MORE   MARRIAGE  CUSTOMS. 


119 


By  the  time  he  reaches  another  plant  they  have 
assumed  such  a  position  that  they  are  brought 
into  contact  with  the  stigma  as  he  sucks  the 
honey.  But  the  stigma  is  gummy  too,  and  makes 
the  pollen  adhere  to  it,  and  in  this  way  cross- 
fertilisation  is  rendered  almost 
a  dead  certainty.  The  result 
of  these  various  clever  dodges 
is  that  the  orchids  have  become 
one  of  the  dominant  plant- 
families  of  the  world,  and  in 
the  tropics  usurp  many  of  the 
best  and  most  favoured  posi- 
tions (Fig.  24). 

Darwin  has  written  a  most 
romantic  book  on  the  numer- 
ous devices  by  which  orchids 
alone  attract  insects  to  fertil- 
ise them.  I  will  say  no  more 
of  this  family,  therefore — the 
highest  and  strangest  among 
the  threefold  flowers — save  merely  to  advise  those 
who  wish  to  know  more  of  this  curious  sub- 
ject to  look  it  up  in  his  charming  volume.  In- 
stead of  pursuing  the  matter  at  issue  further,  I 
will  give  one  final  example  in  an  opposite  direc- 
tion. 

An  opposite  direction,  I  say,  because  all  the 
threefold  flowers  we  have  hitherto  been  consider- 
ing are  examples  of  a  strict  upward  movement  of 
evolution.  Each  group  we  have  examined  has 
been  higher  and  more  complex  than  the  group 
before  it.  But  I  will  now  show  you  an  instance, 
if  not  of  degeneracy,  at  least  of  extreme  simplifi- 
cation, which  yet  produces  in  the  end  the  best 
possible    results.     This    instance  is  that    of   the 


Fig.  24. — The  two  pol- 
len -  masses,  very 
much  enlarged. 


I20 


THE   STORY   OF   THE   PLANTS. 


common    English    arum,    known    to    children    as 
cuckoo-pint  or  "  lords  and  ladies  "  (Fig.  25). 

The  structure  of  the  cuckoo-pint  is  very  pe- 
culiar. What  looks  like  the  flower  is  not  really 
any  part   of   the  flower  at   all,  but   a  large  outer 


Fig.  25. — The  common  arum,  or  cuckoo-pint,  showing  the  spathe 
which  surrounds  the  flowers,  and  the  spike  sticking  up  in  the 
middle. 


leaf  or  spathe  surrounding  a  group  of  very  tiny 
blossoms.  You  can  understand  this  leaf  better 
if  you  look  at  a  narcissus  stalk,  where  a  very 
similar  leaf  is  seen  to  enclose  a  whole  bunch  of 


MORE   MARRIAGE   CUSTOMS. 


21 


buds  and  opening  flowers.  Only,  in  the  narcissus 
the  spathe  is  thin,  whitish,  and  papery,  while  in 
the  cuckoo-pint  it  is  expanded,  green,  and  purple. 
Though  not  a  corolla,  it  serves  the  same  purpose 
as  a  corolla  generally  performs :  it  attracts  insects 
to  the  compound  flower-head. 

Inside  the  spathe  we  find  a  curious  club-shaped 
mass,  coloured  bright  purple,  and  standing  straight 
up  in  the  middle  of  the  head. 
This  is  the  stem  or  axis  on  which 
the  separate  little  flowers  are  ar- 
ranged. Cut  open  the  spathe,  and 
you  will  find  these  flowers  below 
in  the  centre  (Fig.  26).  At  first 
sight  what  you  see  will  look  like 
a  lot  of  confused  little  knobs  ; 
but  when  you  gaze  closer  you 
will  see  they  separate  themselves 
into  three  groups,  which  are  the 
true  flowers.  Lowest  of  all  on 
the  stem  come  the  female  blos- 
soms, without  calyx  or  corolla, 
each  consisting  of  a  single  ovary. 
Above  these  in  a  group  come  the 
male  flowers,  equally  devoid  of 
calyx  or  corolla,  and  each  con- 
sisting of  a  single  stamen.  Above 
these  again  come  abortive  or  mis- 
shapen flowers,  each  of  which  has 
been  reduced  to  a  single  down- 
ward-pointing hair.  I  will  ex- 
plain first  what  is  the  use  of  these  flowers  in  the 
cuckoo-pint  as  it  stands  to-day,  and  then  I  will 
go  back  to  consider  by  what  steps  the  plant  came 
to  develop  them. 

The  upper  flowers,  which  look  like  hairs,  and 


122  THE    STORY   OF   THE    PLANTS. 

point  all  downwards,  occupy  a  place  in  the  com- 
pound flower-head  just  opposite  the  conspicuous 
narrowed  part  of  the  spathe  which  surrounds  and 
encloses  them.  At  this  narrow  point  they  form  a 
sort  of  lobster-pot.  It  is  easy  enough  for  an  in- 
sect to  creep  down  past  them,  but  very  dilificult 
or  impossible  for  him  to  creep  up  in  the  opposite 
direction,  as  all  the  hairs  point  sharply  downwards. 
Now,  when  the  spathe  unfolds,  large  numbers  of 
a  very  small  midge  of  a  particular  species  are  at- 
tracted into  it  by  the  purple  club  which  rises 
like  a  barber's  pole  in  the  middle.  If  you  cut  a 
cuckoo-pint  open  during  its  flowering  period  you 
will  always  find  a  whole  mob  of  these  wee  flies, 
crawling  about  in  it  vaguely,  and  covered  from 
head  to  foot  with  pollen.  They  have  come  from 
another  cuckoo-pint  which  they  previously  visited, 
and  they  have  brought  the  pollen  with  them  on 
their  wings  and  bodies.  But  when  they  first 
reach  the  head,  they  find  no  pollen  there  ;  the 
female  flowers  at  the  bottom  ripen  first,  and  the 
midges,  creeping  over  the  sensitive  surface  of 
these,  fertilise  them  with  pollen  from  the  last 
plant  they  entered.  Finding  nothing  to  eat,  if 
they  could  they  would  crawl  out  again  ;  but  they 
can't,  for  the  lobster-pot  hairs  prevent  them.  So 
they  stop  on  perforce,  having  unwittingly  fertilised 
the  female  flowers,  but  received  themselves  as  yet 
no  reward  for  their  trouble.  By  and  by,  how- 
ever, after  all  the  female  flowers  have  been  duly 
fertilised,  the  males  above  begin  to  ripen.  When 
the  stamens  reach  maturity,  they  shower  down  a 
whole  flood  of  golden  pollen  on  the  expectant 
midges.  Then  the  midges  positively  roll  and 
revel  in  the  flood,  eating  all  they  can,  but  at  the 
same  time  covering  themselves  all   over  with  a 


MORE   MARRIAGE  CUSTOMS.  1 23 

dust  of  pollen-grains.  As  soon  as  the  pollen  is 
all  shed,  the  downward-pointing  hairs  wither 
away ;  the  lobster-pot  ceases  to  act  ;  and  the 
midges  are  at  liberty  to  fly  away  to  another  plant, 
where  they  similarly  begin  to  fertilise  the  female 
flowers.  Observe  that,  if  the  stamens  were  the 
first  to  ripen  here,  the  pollen  would  fall  on  the 
stigmas  of  the  same  plant,  but  that,  by  making 
the  stigmas  be  the  first  to  mature,  the  cuckoo-pint 
secures  for  itself  the  desired  end  of  cross-fertili- 
sation. 

In  this  case  it  is  an  interesting  fact  that  all 
the  stages  which  led  to  the  existing  arrangement 
of  the  flowers  still  remain  visible  in  other  plants 
for  us.  These  very  reduced  little  blossoms  of  the 
cuckoo-pint,  consisting  each  of  a  single  carpel  or 
a  single  stamen,  are  yet  the  descendants  of  per- 
fect blossoms  which  had  once  a  regular  calyx  and 
corolla.  Near  relations  of  the  cuckoo-pint  live  in 
Europe  and  Africa  to  this  day,  which  recapitulate 
for  us,  as  it  were,  the  various  stages  in  its  slow  evo- 
lution. Some,  the  oldest  in  type,  have  a  calyx 
and  corolla,  green  and  inconspicuous,  with  six 
stamens  inside  them,  enclosing  a  two  or  three- 
celled  ovary.  These  are  still  essentially  lilies  in 
structure.  But  they  have  the  flowers  clustered, 
as  in  cuckoo-pint,  on  a  thick  club-stem,  and  they 
have  an  open  spathe,  which  more  or  less  protects 
them.  Our  English  sweet-sedge  is  still  at  this 
stage  of  evolution.  The  marsh-calla  of  Northern 
Europe  and  Canada,  on  the  other  hand,  has  a 
handsome  white  spathe  to  attract  insects,  while 
its  separate  flowers,  still  both  male  and  female  to- 
gether, have  each  six  stamens  and  a  single  ovary. 
But  they  have  lost  their  perianth.  The  common 
white  arum  or  "  calla  lily  "  of  cottage  gardens  has 


124  THE   STORY   OF  THE   PLANTS. 

a  bright  yellow  spike  in  its  midst,  and  if  you  look 
at  it  closely  you  will  see  that  this  spike  consists 
entirely  of  a  great  cluster  of  stamens,  thickly 
massed  together.  The  top  of  the  spike  is  en- 
tirely composed  of  such  golden  stamens,  but  lower 
down  you  will  find  ovaries  embedded  here  and 
there  among  them,  each  ovary  as  a  rule  sur- 
rounded by  five  or  six  stamens.  Lastly,  in  the 
cuckoo-pint  the  lower  flowers  have  lost  their  com- 
plement of  stamens  altogether,  while  the  upper 
ones  have  similarly  lost  their  ovaries  ;  moreover, 
a  few  of  the  topmost  have  been  converted  into 
the  curious  lobster-pot  hairs  which  assist,  as  I 
have  shown  you,  in  the  work  of  fertilisation. 
We  have  here  a  singular  and  instructive  exam- 
ple of  what  may  be  described  as  retrograde  develop- 
ment. 

And  now  we  must  go  on  to  those  modes  of 
fertilisation  which  are  effected  by  agencies  other 
than  insects. 


CHAPTER   IX. 

THE    WIND    AS    CARRIER. 

All  flowers  do  not  depend  for  fertilisation 
upon  insects.  In  many  plants  it  is  the  wind  that 
serves  the  purpose  of  common  carrier  of  pollen 
from  blossom  to  blossom. 

Clearly,  flowers  which  lay  themselves  out  to 
be  fertilised  by  the  wind  will  not  be  likely  to  pro- 
duce the  same  devices  as  those  which  lay  them- 
selves out  to  be  fertilised  by  insects.  Natural 
selection  here  will  favour  different  qualities. 
Bright-coloured  petals  and  stores  of  honey  will 


THE   WIND   AS   CARRIER.  125 

not  serve  to  allure  the  unconscious  breeze;  such 
delicate  adjustments  of  part  to  part  as  we  saw  in 
the  case  of  bee  and  blossom  will  no  longer  be 
serviceable.  What  will  most  be  needed  now  is 
quantities  of  pollen  ;  and  that  pollen  must  hang 
out  in  such  a  way  from  the  cup  as  to  be  easily 
dislodged  by  passing  breezes.  Hence  wind-fertil- 
ised flowers  differ  from  insect-fertilised  in  the 
following  particulars.  They  have  never  brilliant 
corollas  or  calyxes.  The  stamens  are  usually 
very  numerous;  they  hang  out  freely  on  long 
stalks  or  filaments ;  and  they  quiver  in  the  wind 
with  the  slightest  movement.  On  the  other  hand, 
the  stigmas  are  feathery  and  protrude  far  from 
the  flower,  so  as  to  catch  every  passing  grain  of 
pollen.  More  frequently  than  among  the  insect- 
fertilised  section,  the  sexes  are  separated  on  dif- 
ferent plants  or  isolated  in  distinct  masses  on 
neighbouring  branches.  But  numerous  devices 
occur  to  prevent  self-fertilisation. 

You  must  not  suppose,  again,  that  the  wind- 
fertilised  plants  form  a  group  by  themselves,  dis- 
tinct in  origin  from  the  insect-fertilised,  as  the 
three-petalled  group  is  distinct  from  the  five- 
petalled.  On  the  contrary,  wind-fertilised  kinds 
are  found  abundantly  in  both  great  groups;  it  is 
a  matter  of  habit;  so  much  so  that  sometimes  a 
type  has  taken  first  to  insect-fertilisation  and  then 
to  wind-fertilisation,  with  comparatively  slight 
differences  in  its  external  appearance.  Closely 
related  plants  often  differ  immensely  in  their  mar- 
riage customs;  each  has  varied  in  the  way  that 
best  suited  itself,  according  as  insects  or  breezes 
happened  to  serve  it  most  readily.  In  my  own 
opinion  all  wind-fertilised  plants  are  the  descend- 
ants of  insect-fertilised  ancestors ;  but  I  do  not 


126  THE    STORY   OF  THE   PLANTS. 

know  whether  in  this  behef  my  ideas  would  be 
accepted  by  most  modern  botanists. 

As  a  first  example  of  wind-fertilised  flowers,  I 
will  take  the  common  dog's  mercury,  a  well- 
known  English  wayside  flower,  frequent  in  copses 
and  hedgerows,  and  one  of  the  very  earliest  to 
blossom  in  spring.  In  this  species  the  males  and 
females  grow  on  separate  plants.  They  have 
each  a  calyx  of  three  sepals  (two  more  being  sup- 
pressed, for  they  belong  by  origin  to  the  fivefold 
division).  .The  males  have  ten  or  twelve  stamens 
apiece,  which  hang  out  freely  with  long  stalks  to 
the  breeze.  The  females  have  a  two-chambered 
ovary,  with  rudiments  or  relics  of  some  two  or 
three  stamens  by  its  side,  showing  that  they  are 
descended  from  earlier  combined  male-and-female 
ancestors.  The  relics,  however,  consist  of  mere 
empty  stalks  or  filaments,  without  any  pollen- 
sacks.  Of  course  there  are  no  petals.  Male  and 
female  plants  grow  in  little  groups  not  far  from 
one  another ;  and  the  pollen,  which  is  dry  and 
dusty,  is  carried  by  the  wind  from  the  hanging 
stamens  of  the  males  to  the  large  and  salient 
stigma  of  the  female  flowers. 

A  still  better  example  of  a  wind-fertilised 
blossom  is  afforded  us  by  the  common  English 
salad-burnet,  a  pretty  little  weed,  very  frequent 
on  close-cropped  chalk  downs  (Fig.  27).  Here 
the  individual  flowers  are  extremely  small,  and 
they  are  crowded  into  a  sort  of  mop-like  head  at 
the  top  of  the  stem.  They  have  lost  their  petals, 
which  are  now  of  no  use  to  them ;  but  they  retain 
a  calyx  of  four  sepals,  to  represent  the  original 
five  still  found  among  their  relations.  For  salad- 
burnet,  in  spite  of  its  inconspicuousness,  belongs  to 
the  family  of  the  roses,  and  we  can  still  trace  in 


THE   WIND   AS  CARRIER. 


127 


this  order  a  regular  gradation  from  handsome 
flowers  like  the  dog-rose,  through  smaller  and 
smaller  blossoms  like  the  strawberry  and  the 
potentilla,  to  green  petalless  types  like  lady's- 
mantle  and  parsley-piert,  or,  last  of  all,  to  wind- 
fertilised  blossoms  like  those  of  the  salad-burnet. 
In  the  male  flowers  the  very  numerous  stamens 
hang  out  on  long  thread-like  stalks  from  the  wee 
green  cup,  so  that 
the  wind  may  readily 
catjch  and  carry  the 
poflen  ;  in  the  female 
blossoms  the  stigma 
is  divided  into  plume- 
like brushes,  which 
readily  entrap  any 
passing  pollen-grain. 
Moreover,  though 
both  kinds  of  flower 
grow  on  the  same 
head,  the  females  are 
mostly  at  the  top  of 
the  bunch  and  the 
males    below    them. 

This  makes  it  difficult  for  the  pollen  from  the  same 
head  to  fertilise  the  females,  as  it  would  easily  do 
if  the  males  were  at  the  top.  Nor  is  that  all ;  the 
female  flowers  open  first  on  each  head,  and  hang 
out  their  pretty  feathery  stigmas  to  the  breeze 
that  bends  the  stem  ;  as  soon  as  they  have  been 
fertilised  from  a  neighbour  plant,  the  males  in 
turn  begin  to  open,  and  shed  their  pollen  for  the 
use  of  other  flowers.  In  salad-burnet,  however, 
the  division,  of  the  sexes  into  separate  flowers  has 
not  become  a  quite  fixed  habit;  for,  though  most 
of  the  blossoms  are  either  male  or  female  only, 


Fig.  27.— a,  male,  and  B,  female 
flower  of  salad-burnet,  very  much 
magnified.  The  flowers  grow  to- 
gether in  little  tassel-like  heads. 


128  THE   STORY   OF  THE   PLANTS. 

as  shown  in  the  figure,  we  often  find  a  cup  here 
and  there  which  contains  both  stamens  and  pistil 
together. 

I  have  already  told  you  that  in  many  plants 
the  calyx  helps  the  corolla  as  an  advertisement 
for  insects;  and  sometimes,  as  in  the  marsh- 
marigold  and  the  various  anemones,  where  there 
are  no  petals  at  all,  it  becomes  so  brilliant  as  to 
be  mistaken  for  petals  by  all  but  botanists.  One 
way  in  which  such  a  substitution  often  happens 
is  shown  us  by  the  great  burnet,  which  is  a  close 
relation  of  the  salad-burnet.  This  plant,  after 
having  acquired  the  habit  of  wind-fertilisation, 
has  taken  again  at  last  to  insect  marriage.  Hav- 
ing lost  its  petals,  however,  it  can't  easily  rede- 
velop them ;  so  it  has  had  instead  to  make  its 
calyx  purple.  The  plant  as  a  whole  closely  re- 
sembles the  salad-burnet;  but  the  flowers  are 
rather  different  ;  the  stamens  no  longer  hang  out 
of  the  calyx;  the  calyx  cup  is  more  tubular;  and 
the  stigma  is  shortened  to  a  little  sticky  knob, 
instead  of  being  divided  into  feathery  fringes. 
These  differences  are  all  very  characteristic  of 
the  contrast  between  wind  and  insect-fertilisation. 

The  common  nettle  supplies  us  with  an  excel- 
lent example  of  another  form  of  wind-fertilisa- 
tion, carried  to  a  still  higher  pitch  of  develop- 
ment. Here  the  sexes  grow  on  different  plants, 
and  the  flowers  are  tiny,  green,  and  inconspicu- 
ous. The  males  consist  of  a  calyx  of  four  sepals, 
each  sepal  with  a  stamen  curiously  caught  under 
it  during  the  immature  stage.  But  as  soon  as  they 
ripen  they  burst  out  elastically,  and  shoot  their 
pollen  into  the  air  around  them.  In  this  case, 
and  in  many  like  it,  the  plant  itself  helps  the 
wind,  as  it  were,  to  disseminate  its  pollen. 


THE   WIND   AS   CARRIER. 


129 


The  common  English  bur- 
reed  is  a  waterside  plant  of 
great  beauty  which  shows  us 
another  interesting  instance 
of  wind-fertilisation  in  an  ad- 
vanced condition  (Fig.  28). 
Here  the  separate  flowers  are 
very  much  reduced — as  sim- 
ple, in  fact,  as  those  of  the 
cuckoo-pint.  The  males  con- 
sist of  nothing  but  stamens, 
gathered  in  close  globular 
heads,  with  a  few  small  scales 
interspersed  among  them, 
which  seem  to  represent  the 
last  relics  of  a  calyx.  The 
females  are  made  up  of  single 
ovaries,  each  surrounded  by 
three  or  six  scales,  still  form- 
ing a  simple  rudimentary  ca- 
lyx. They,  too,  are  clustered 
in  round  heads  or  masses  on 
antler -like  branches.  The 
plant  belongs  to  the  threefold 
group,  and  represents  a  very 
degenerate  descendant  of  a 
primitive  ancestor  something 
like  the  arrowhead  already 
described  in  the  last  chapter. 
But  the  arrangement  of  the 
heads  on  the  stem  is  very  in- 
teresting. The  balls  at  the 
top  are  entirely  composed  of 
male  flowers;  those  at  the 
bottom  are  exclusively  female, 
ers  ripen  first,  and  receive  pollen  by  aid  of  the 
9 


Fig.  28. — Flowers  of  bur- 
reed.  The  two  lower 
heads  consist  of  female 
blossoms,  the  five  upper 
ones  of  males.  Only 
one  head  of  the  males 
is  mature ;  the  others 
are  still  in  the  bud. 

The  female  flow- 


130  THE   STORY  OF  THE    PLANTS. 

wind  from  some  other  plant  that  grows  close  by 
them.  As  soon  as  they  have  begun  to  set  their 
seeds  the  stigmas  wither,  and  then  the  male  flow- 
ers open  in  a  bright  yellow  mass,  the  stalks  of 
their  stamens  lengthening  out  as  they  do  so,  and 
allowing  the  wind  to  carry  the  pollen  freely. 
Here,  although  the  males  are  above,  the  peculiar 
arrangement  by  which  the  females  ripen  first 
makes  it  practically  impossible  for  the  flowers  to 
be  fertilised  by  pollen  from  their  immediate  neigh- 
bours. 

The  devices  for  wind-fertilisation,  however, 
are  on  the  whole  less  interesting  than  those  for 
insect-fertilisation,  so  I  shall  devote  little  more 
space  to  describing  them.  I  will  only  add  that 
two  great  classes  of  plants  are  habitually  wind- 
fertilised  :  one  includes  the  majority  of  forest 
trees;  the  other  includes  the  grasses,  sedges,  and 
many  other  common  meadow  plants. 

The  wind-fertilised  forest  trees  belong  for  the 
most  part  to  the  fivefold  group,  and  have  their 
flowers,  as  a  rule,  clustered  together  into  bang- 
ing and  pendulous  bunches,  which  we  call  catkins. 
It  is  obvious  why  trees  should  have  adopted  this 
mode  of  fertilisation,  because  they  grow  high,  and 
it  is  easy  for  the  wind  to  move  freely  through  them. 
For  this  reason,  most  catkin-bearing  trees  flower 
in  early  spring,  when  winds  are  high,  and  when 
the  trees  are  leafless;  because  then  the  foliage 
doesn't  interfere  with  the  proper  carriage  of  the 
pollen.  In  summer  the  leaves  would  get  in  the 
way ;  the  pollen  would  fall  on  them ;  and  the 
stigmas  would  be  hidden.  Most  catkins  are  long, 
and  easily  moved  by  the  wind ;  they  have  numer- 
ous flowers  in  each,  and  they  shake  out  enormous 
quantities  of  pollen.     This  you  can  see  for  your- 


THE   WIND   AS   CARRIER.  13 1 

self  by  shaking  a  hazel  branch  in  the  flowering 
season,  when  you  will  find  yourself  covered  by  a 
perfect  shower  of  pollen. 

In  hazel  (Fig.  29)  the  male  and  female  flowers 
grow  on  the  same  tree,  but  are  most  different  to 
look  at.  You  would  hardly  take  them  for  cor- 
responding parts  of  the  same  species.  The  male 
flowers  are  grouped  in  long  sausage-shaped  cat- 
kins, each  blossom  covered  with  a  tiny  brown 
scale,  and  all  arranged  like  tiles  on  a  roof  against 
the  cold  of  winter.  There  are  about  eight  sta- 
mens to  each  blossom,  with  little  trace  of  a  calyx 


Fig.  29  —  Flowers  of  the  hazel.  I,  a  single  male  flower,  removed 
from  a  catkin  ;  II,  a  pair  of  female  flowers  ;  III,  a  female 
catkin. 

or  corolla.  But  the  females  are  grouped  in  funny 
little  buds,  like  crimson  tufts,  well  protected  by 
scales;  they  consist  of  the  future  hazel-nut,  with 
a  red  style  and  feathery  stigma  projecting  above 
to  catch  the  pollen.  Here  the  flowers  are  very 
little  like  the  regular  types  with  which  we  are 
familiar ;  yet  intermediate  cases  help  to  bridge 
over  the  gap  for  us. 

For  example,  in  the  alder  we  get  a  type  which 
seems  to  stand  half-way  between  the  nettle  and 
the  hazel  (so  far,  I  mean,  as  the  arrangement  of 
the  flower  is  concerned,  for  otherwise  the  nettle 


132  THE  STORY  OF  THE   PLANTS. 

belongs  to  a  quite  different  family).  The  male 
and  female  catkins  of  the  alder  grow  on  the  same 
tree;  the  males  consist  of  numerous  clustered 
flowers,  three  together  under  a  scale,  which  never- 
theless, when  we  take  the  trouble  to  pick  them 
out  and  examine  them  with  a  pocket-lens,  are 
seen  to  resemble  very  closely  the  male  flowers  of 
the  nettle.  Each  consists  of  a  four-lobed  calyx, 
with  four  stamens  opposite  the  sepals.  The  fe- 
male flowers  have  degenerated  still  further,  and 
consist  of  little  more  than  a  scale  and  an  ovary. 

Other  well-known  wind-fertilised,  catkin-bear- 
ing trees  are  the  oak,  the  beech,  the  birch,  and  the 
hornbeam.  But  the  willows,  though  they  bear 
catkins,  and  were  once  no  doubt  wind-fertilised, 
have  now  returned  once  more  to  insect-fertilisa- 
tion, as  you  can  easily  convince  yourself  if  you 
stand  under  a  willow  tree  in  early  spring,  when 
you  will  hear  all  the  branches  alive  with  the  buzz- 
ing of  bees,  both  wild  and  domestic.  Neverthe- 
less, the  willow,  having  once  lost  its  petals,  has 
been  unable  to  develop  them  again.  Still,  its 
catkins  are  far  handsomer  and  more  conspicuous 
than  those  of  its  wind-fertilised  cousins,  owing  to 
the  pretty  white  scales  of  the  female  bunches,  and 
the  numerous  bright  yellow  stamens  of  the  males. 
It  is  this  that  causes  them  to  be  used  for  "palm  " 
in  churches  on  Palm  Sunday.  The  male  and  fe- 
male catkins  grow  on  different  trees,  so  as  to  en- 
sure cross-fertilisation,  and  the  difference  between 
the  two  forms  is  greater  perhaps  than  in  almost 
any  other  plant,  the  males  consisting  of  two 
showy  stamens  behind  a  winged  scale,  and  the 
females  of  a  peculiar  woolly-looking  ovary. 

Even  more  important  is  the  great  wind-fertil- 
ised group  of  the  grasses,  to  which  belong  by  far 


THE  WIND  AS   CARRIER.  133 

the  most  useful  food-plants  of  man,  such  as  wheat, 
rice,  barley,  Indian  corn,  and  millet. 

Grasses  are  for  the  most  part  plants  of  the 
open  wind-swept  plains,  and  they  seem  naturally 
to  take  therefore  to  wind-fertilisation.  Their 
flowers  are  generally  small,  clustered  into  light 
spikes  or  waving  panicles,  and  hung  out  freely  to 
the  breeze  on  slender  and  very  movable  stems, 
so  as  to  yield  their  pollen  to  every  breath  of  air 
that  passes.  Moreover,  the  plants  as  a  whole  are 
slender  and  waving,  so  that  they  bend  before  the 
breeze  in  the  mass,  as  one  often  sees  in  a  meadow 
or  cornfield.  Thus  the  grasses  are  almost  the 
pure  type  of  wind-fertilised  plants;  certainly 
they  have  carried  further  than  any  other  race 
the  devices  which  render  wind-fertilisation  more 
certain. 

On  this  account  they  are  so  complicated  and 
varied  that  I  will  not  attempt  to  describe  them  in 
detail.  I  will  only  say  that  grasses  are  descend- 
ants of  the  threefold  flowers,  and  in  all  proba- 
bility degenerate  lilies.  Their  individual  blos- 
soms usually  consist  of  a  very  degraded  calyx 
(^and  e)  of  two  sepals  (one  of  which  represents  a 
pair  that  have  coalesced.  Fig.  30).  Inside  these 
sepals  come  two  very  minute  white  petals  (c  and 
c) ;  the  third  has  disappeared,  owing  to  pressure 
one-sidedly.  The  petals  can  scarcely  be  seen 
without  the  aid  of  a  pocket-lens.  Next  comes 
three  stamens  (d),  the  only  part  of  the  flower 
which  still  preserves  the  original  threefold  ar- 
rangement. Last  of  all  we  get  the  ovary  (a),  of 
one  carpel,  one  seeded,  but  with  two  feathery 
stigmas,  which  were  once  three.  In  a  very  few 
large  grasses,  such  as  the  bamboos,  the  threefold 
arrangement    is   much   more   conspicuous.     As  a 


134 


THE   STORY  OF  THE   PLANTS. 


rule  the  stamens  of  grasses  hang  out  freely  to 
the  wind,  and  the  stigmas  are  feathery  and  most 
graceful  in  outline  (Fig.  31).  The  flowers  are 
usually  collected  in  spikes  like  that  of  wheat,  or 
in  loose  clusters  like  oats;  they  frequently  hang 
over  in  pendulous  bunches.     Their  success  may 


Fig.  30. — A  flower  of  wheat, 
with  its  parts  divided,  a, 
the  carpel  and  stigmas ;  b^ 
the  stamens  ;  c,  the  petals, 
very  minute ;  d  and  ^,  the 
calyx. 


Fig.  31.— Flower  of  wheat,  with 
the  calyx  of  two  chaffy  scales 
removed  This  shows  the 
arrangement  of  petals,  sta- 
mens, and  ovary. 


be  gathered  from  the  fact  that  almost  all  the 
great  plains  in  the  world,  such  as  the  American 
prairies,  the  Pampas,  and  the  Steppes,  are  covered 
with  grasses;  while  even  in  hilly  countries  the 
valleys  and  downs  are  also  largely  clad  with 
smaller  and  more  delicate  species.  No  plants 
assume  so  great  a  variety  of  divergent  forms; 
the  total  number  of  kinds  of  grasses  can  hardly 
be  estimated ;  in  Britain  alone  we  have  more 
than  a  hundred  native  species. 


HOW  FLOWERS  CLUB  TOGETHER.  135 

I  will  give  no  further  examples  of  wind- 
fertilised  flowers.  If  you  look  for  yourself  you 
can  find  dozens  on  all  sides  in  the  fields  around 
you.  They  may  almost  always  be  recognised  by 
these  two  marked  features  of  the  hanging  stamens 
and  the  feathery  stigma. 

Before  I  pass  on  to  another  subject,  however, 
I  ought  to  mention  that  by  no  means  all  flowers 
are  regularly  cross-fertilised.  There  are  some 
degraded  types  in  which  self-fertilisation  has  be- 
come habitual.  In  these  plants,  which  are  usually 
poor  and  feeble  weeds  like  groundsel  and  shep- 
herd's purse,  the  stamens  bend  round  so  as  to 
impregnate  the  pistil  in  the  same  blossom.  In 
other  less  degraded  cases  the  flower  is  occasion- 
ally cross-fertilised  by  insect  visits ;  but  if  no 
insect  turns  up  in  time,  the  stamens,  even  in 
handsome  and  attractive  blossoms,  often  bend 
round  and  impregnate  the  pistil.  A  very  good 
example  of  this  is  seen  in  our  smaller  English 
mallow,  which  has  large  mauve  flowers  to  attract 
insects;  but  should  none  come  to  visit  it,  the 
stamens  and  stigmas  at  last  intertwine,  and  self- 
fertilisation  takes  place,  for  want  of  better.  Still, 
as  a  general  rule,  it  holds  good  that  self-fertilisa- 
tion belongs  to  scrubby  and  degraded  plants;  it 
is  only  adopted  as  a  last  resort  when  all  other 
means  fail  by  the  superior  species. 


CHAPTER   X. 

HOW    FLOWERS    CLUB    TOGETHER. 

In  the  preceding  chapters  I  have  dealt  for  the 
most  part  with  individual  flowers;  I  have  spoken 


136  THE   STORY  OF   THE   PLANTS. 

of  them  separately,  and  of  the  work  they  do  in 
getting  the  seeds  set.  Incidentally,  however,  it 
has  been  necessary  at  times  to  touch  slightly  upon 
the  way  they  often  mass  themselves  into  heads 
or  clusters  for  various  purposes;  and  we  must 
now  begin  to  consider  more  seriously  the  origin 
and  nature  of  these  co-operative  societies. 

Very  large  flowers,  like  the  w^ater-lily,  the 
tulip,  the  magnolia,  the  daffodil,  are  usually  soli- 
tary;  they  suffice  by  themselves  to  attract  in 
sufficient  numbers  the  fertilising  insects.  But 
smaller  flowers  often  find  it  pays  them  better  to 
group  themselves  into  big  spikes  or  masses,  as 
one  sees,  for  example,  in  the  foxglove  and  the 
lilac.  Such  an  arrangement  makes  the  mass  more 
conspicuous,  and  it  also  induces  the  insect,  when 
he  comes,  to  fertilise  at  a  single  visit  a  large  num- 
ber of  distinct  blossoms.  It  is  a  mutual  conven- 
ience;  for  the  bee  or  butterfly,  it  saves  valuable 
time;  for  the  plant,  it  ensures  more  prompt  and 
certain  fertilisation.  In  many  families,  therefore, 
we  can  trace  a  regular  gradation  between  large 
and  almost  solitary  flowers,  through  smaller  and 
somewhat  clustered  flowers,  to  very  small  and 
comparatively  crowded  flowers.  Thus  the  largest 
lilies  are  usually  solitary  or  grow  at  best  three  or 
four  together,  like  the  lilium  auratum ;  in  the 
tuberose  and  asphodel,  where  the  individual  blos- 
soms are  smaller,  they  are  gathered  together  in 
big  upright  spikes;  in  the  hyacinth,  the  clustering 
is  closer  still;  while  in  wild  garlic,  grape-hya- 
cinth, and  star-of-Bethlehem,  the  arrangement 
assumes  the  form  of  a  flat-topped  bunch  or  a 
globular  cluster.  Of  course,  small  flowers  are 
sometimes  solitary,  and  large  ones  sometimes 
clustered;  but  as  a  general  rule  the  tendency  is 


HOW   FLOWERS   CLUB   TOGETHER.  137 

for  the  big  blossoms  to  trust  to  their  own  indi- 
vidual attractions,  and  for  the  little  ones  to  feel 
that  union  is  strength,  and  to  organise  accord- 
ingly. 

Botanists  have  invented  many  technical  names 
for  various  groupings  of  flowers  in  particular 
fashions,  with  most  of  which  I  will  not  trouble 
you.  It  will  be  sufficient  to  recall  mentally  the 
very  different  way  in  which  the  flowers  are  ar- 
ranged in  the  lily-of-the-valley,  the  foxglove,  the 
Solomon's  seal,  the  heath,  the  scabious,  the  cow- 
slip, the  sweet-william,  the  forget-me-not,  in  order 
to  see  what  variety  natural  selection  has  produced 
in  all  these  matters.  Two  instances  must  serve 
to  illustrate  their  mode  of  action.  The  foxglove 
grows  in  hedgerows  and  thickets,  and  turns  its 
one-sided  spike  towards  the  sun  and  the  open  ;  its 
flowers  open  regularly  from  below  upward,  and  are 
fertilised  by  bees,  who  enter  the  blossoms,  and 
whose  body  is  beautifully  adapted  to  come  in 
contact,  first  with  the  stamens,  and  later  with  the 
stigma.  (Examine  this  familiar  flower  for  your- 
self in  the  proper  season.)  In  the  forget-me-not, 
on  the  other  hand,  the  unopened  flowers  are 
coiled  up  like  a  scorpion's  tail ;  but  as  each  one 
opens,  the  stem  below  it  lengthens  and  unrolls,  so 
that  at  each  moment  the  two  or  three  flowers  just 
ready  for  fertilisation  are  displayed  conspicuously 
at  the  top  of  the  apparent  cluster. 

There  are  two  forms  of  cluster,  however,  so 
specially  important  that  I  cannot  pass  them  over 
here  without  some  words  of  explanation.  These 
are  the  umbel  and  the  head,  both  of  frequent  oc- 
currence. An  umbel  is  a  cluster  in  which  the 
flowers,  standing  on  separate  stalks,  reach  at  last 
the  same  level,  so  as  to  form  a  flat-topped  mass, 


138  THE   STORY   OF   THE   PLANTS. 

like  the  surface  of  a  table.  An  immense  family 
of  plants  has  very  small  flowers  arranged  in  such 
an   order ;    they  are    known   as    umbellates,   and 


Fig.  32. — Clusters  of  flowers.  I,  spike  of  niercary,  green,  wind- 
fertilised  ;  II,  panicle  of  a  grass  (brome),  green,  wind-fertilised  ; 
HI,  head  of  Dutch  clover,  the  upper  flowers  unvisited  as  yet 
by  insects ;  the  lower  fertilised,  and  turning  down  to  make 
room  for  their  neighbours. 

they  include  hemlock,  fool's  parsley,  cow-parsnip, 
carrot,  chervil,  celery,  angelica,  and  samphire. 
In  other  families  the  same  form  of  cluster  is  seen 


HOW   FLOWERS   CLUB   TOGETHER.  139 

in  ivy  and  garlic.  A  head,  again,  is  a  cluster  in 
which  the  individual  flowers  are  set  close  on  very 
short  stalks  or  none  at  all  in  a  round  ball  or  a 
circle.  Clover  and  scabious  are  excellent  ex- 
amples of  this  sort  of  co-operation. 

If  you  examine  a  head  of  common  white  Dutch 
clover  (Fig.  32,  iii.),  you  will  see  for  yourself  that 
it  is  not,  as  you  might  suppose,  a  single  flower, 
but  a  thick  mass  of  small  white  pea-like  blos- 
soms, each  on  a  stalk  of  its  own,  and  each  pro- 
vided with  calyx,  corolla,  stamens,  and  pistil. 
They  are  fertilised  by  bees  ;  and  as  soon  as  the 
bee  has  impregnated  each  blossom,  it  turns  down 
and  closes  over,  so  as  to  warn  the  future  visitor 
that  he  has  nothing  to  expect  there.  The  flowers 
open  from  below  and  without,  upward  and  in- 
ward ;  and  there  is  always  a  broad  line  between 
the  rifled  and  fertilised  flowers,  which  hang  down 
as  if  retired  from  business,  and  the  fresh  and  up- 
standing virgin  blossoms,  which  court  the  bees 
with  their  bright  corollas.  Sometimes  you  will 
find  a  head  of  clover  in  which  all  the  flowers  save 
one  have  already  been  fertilised  ;  and  this  one,  a 
solitary  old  maid  as  it  were,  stands  up  in  the  cen- 
tre still  waiting  for  the  bees  to  come  and  ferti- 
lise it. 

By  far  the  most  interesting  form  of  head,  how- 
ever, is  that  which  occurs  in  the  daisy,  the  sun- 
flower, the  dandelion,  and  their  allies,  where  the 
club  01*  co-operative  society  of  united  blossoms  so 
closely  simulates  a  single  flower  as  to  be  univer- 
sally mistaken  for  one  by  all  but  botanical  ob- 
servers. To  the  world  at  large  a  daisy  or  a  dahlia 
is  simply  a  flower  ;  in  reality  it  is  nothing  of  the 
sort,  but  a  city  or  community  of  distinct  flowers, 
differing  widely    from   one   another  in  structure 


140 


THE   STORY   OF  THE   PLANTS. 


and  function,  but  all  banded  together  in  due  sub- 
ordination for  the  purpose  of  effecting  a  common 
object.  There  is  avast  and  very  varied  family  of 
such  united  flowers,  known  as  the  composites;  it 
stands  at  the  head  of  the  fivefold  group  of  flower- 
ing plants,  as  the  orchids  stand  at  the  head  of  the 
threefold ;  and  it  is  so  widely  spread,  it  includes 
so  large  a  proportion  of  the  best-known  plants, 
and  it  fills  so  great  a  space  in  the  vegetable  world 
generally,  that  I  cannot  possibly  pass  it  over  even 


Fig.  33. — Single  floret  from  the 
centre  of  a  daisy. 


Fig.  34. — Single  floret  from  the 
centre  of  a  daisy,  with  the  co- 
rolla opened,  much  enlarged 


in  SO  brief  and  hasty  a  history  as  this  of  the  de- 
velopment of  plants  on  the  surface  of  our  planet. 
If  you  pick  a  daisy  you  will  think  at  first 
sight  it  is  a  single  flower.  But  if  you  look  closer 
into  it  you  will  see  it  is  really  a  great  group  of 
flowers — a  compound  flower-head,  composed  of 
many  dozen  distinct  blossoms  or  florets,  as  we 
call  them  (Fig.  i^).  These,  however,  are  not  all 
alike.  The  florets  in  the  centre,  which  you  took 
no  doubt  at  first  sight  for  the  stamens  and  pistils, 
are  small  yellow  tubular  blossoms,  each  with  a 


HOW   FLOWERS   CLUB   TOGETHER. 


141 


combined  corolla  of  five  lobes,  little  or  no  visible 
calyx,  five  stamens  united  in  a  ring  round  the 
style,  and  a  pistil  consisting  of  an  inferior  ovary, 
with  a  style  divided  above  into  a  twofold  stigma 
(Fig.  34).  Here  we  have  clear  evidence  that  the 
plant  belongs  by  origin  to  the  five-petalled  group  ; 
it  rather  resembles  the  harebell,  in  the  plan  of  its 
flower,  on  a  much  smaller  scale ;  but  it  has  almost 
lost  all  trace  of  a  separate  calyx,  it  has  its  five 
petals  united  into  a  tubular  corolla,  it  has  still  its 
original  five  stamens,  but  its  carpels  are  now  re- 
duced to  one,  with  a  single 
seed,  though  traces  of  an 
earlier  intermediate  stage, 
when  the  carpels  were  two, 
remains  even  yet  in  the  di- 
vided stigma. 

So  much  for  the  inner 
flowers  or  florets  in  the  daisy. 
The  outer  ones,  which  you 
took  at  first  no  doubt  for 
petals,  are  very  different  in- 
deed from  these  central  blos- 
soms. They  have  an  ex- 
tremely curious  long,  strap- 
shaped  corolla  (Fig.35),open 
down  the  side,  but  tubular 
at  its  base,  as  if  it  had  been 
split  through  the  greater  part 
of  its  length  by  a  sharp  pen- 
knife. Instead  of  being  yel- 
low, too,  these  outer  florets  are  white,  slightly 
tinged  with  pink,  and  they  form  the  largest  and 
most  attractive  part  of  the  whole  flower-head. 
Furthermore,  they  are  female  only ;  they  have  a 
style  and  ovary,  but  no  stamens.    Clearly,  we  have 


Fig.  35.— Single  floret  from 
the  ray  of  a  daisy,  pink 
and  white,  with  an 
ovary,  but  no  stamens. 


142  THE   STORY   OF   THE    PLANTS. 

here  a  flower-head  with  numerous  unhke  flowers, 
which  at  once  suggests  the  idea  of  a  division  of 
labour  between  the  component  members.  How 
this  division  works  we  shall  see  in  the  sequel. 

The  best  way  to  see  it  is  to  follow  up  in  detail 
the  evolution  of  the  daisy  and  the  other  com- 
posites from  an  earlier  ancestor.  We  saw  already 
how  the  petals  combined  in  the  harebell  and  many 
other  flowers  so  as  to  form  a  tubular  corolla.  A 
purple  flower  of  some  such  type  seems  to  have 
been  the  starting-point  for  the  development  of 
the  great  composite  family.  The  individual  blos- 
soms in  the  common  ancestral  form  seem  to  have 
been  small  and  numerous  ;  and,  as  often  happens 
with  small  flowers,  they  found  that  by  grouping 
themselves  together  in  a  flat  head  they  succeeded 
much  better  in  attracting  the  attention  of  the  fer- 
tilising insects.  Many  other  tubular  flowers  that 
are  not  composites  have  independently  hit  upon 
the  same  device;  such  are  the  scabious,  the 
devil's-bit,  the  sheep's-bit,  and  the  rampion.  But 
these  flowers  differ  from  the  true  composites  in 
two  or  three  particulars.  In  the  first  place,  each 
tiny  flower  has  a  distinct  green  calyx,  of  five  se- 
pals ;  while  the  composites  have  none,  or  at  least 
a  degraded  one.  In  the  second  place,  the  stamens 
are  free,  while  in  the  composites  they  have  united 
in  a  ring  or  cylinder.  In  the  third  place,  the 
ovary  is  divided  into  from  two  to  five  cells,  a  rem- 
iniscence of  the  original  five  distinct  carpels; 
whereas  in  the  composites  the  ovary  is  always 
single  and  one-seeded.  In  all^  these  respects, 
therefore,  the  composites  are  later  and  more  ad- 
vanced types  than,  say,  the  sheep's-bit,  which  is  a 
flower-head  composed  of  very  tiny  harebells. 

The  composites,  then,  started  with  florets  which 


HOW   FLOWERS   CLUB   TOGETHER.  143 

had  little  or  no  calyx,  the  sepals  having  been  con- 
verted into  tiny  feathery  hairs,  used  to  float  the 
fruit  (as  in  thistledown  and  dandelion),  about 
which  we  shall  have  more  to  say  in  a  future  chap- 
ter. They  had  a  corolla  of  five  purple  petals,  com- 
bined into  a  single  tube.  Inside  this  again  came 
five  united  stamens,  and  in  the  midst  of  all  an  in- 
ferior ovary  with  a  divided  stigma.  Hundreds  of 
different  kinds  of  composites  now  existing  on  the 
earth  retain  to  this  day,  in  the  midst  of  the  great- 
est external  diversity,  these  essential  features,  or 
the  greater  part  of  them. 

You  may  take  thistle  as  a  good  example  of  the 
composite  flowers  in  an  early  and  relatively  simple 
stage  of  development  (Fig.  36).  Here  the  whole 
flower-head  resembles  a  single  large  purple  blos- 
som. To  increase  the  resemblance,  it  has  below 
it  what  seems  at  first  sight  to  be  a  big  green  calyx 
of  very  numerous  sepals.  What  is  this  deceptive 
object  ?  Well,  it  is  called  an  imiolucre^  and  it  really 
acts  to  the  compound  flower-head  very  much  as 
the  calyx  acts  to  the  single  blossom.  The  florets 
having  got  rid  of  their  separate  calyxes,  the  flower- 
head  provides  itself  with  a  cup  of  leaves  (tech- 
nically called  bracts),  which  protect  the  unopened 
head  in  its  early  stages,  and  serve  to  keep  off  ants 
or  other  creeping  insects  exactly  as  a  calyx  does 
for  the  single  flower.  Inside  this  involucre,  again, 
all  the  florets  of  the  thistle  are  equal  and  similar. 
Each  has  a  tiny  calyx,  hardly  recognisable  as 
such,  made  up  of  feathery  hairs  which  cap  the 
inferior  ovary.  Within  this  fallacious  calyx,  once 
more,  the  floret  has  a  purple  corolla  of  five  petals, 
united  into  a  tube.  Then  come  the  five  united 
stamens,  and  the  pistil  with  its  divided  stigma. 
This  is  the  simplest  and  central  form  of  compos- 


144 


THE   STORY   OF   THE    PLANTS. 


ite,   from  which    the    others   are  descended  with 
various  modifications. 

To  this  central  type  belong  a  large  number  of 
well-known  plants,  both  useful  and  ornamental, 
though     more    particularly    deleterious.     Among 

them  may  be  mentioned 
the  various  thistles, 
such  as  the  common 
thistle,  the  milk  thistle, 
the  Scotch  thistle,  and 
so  forth,  most  of  which 
have  their  involucres, 
and  often  their  leaves 
as  well,  extremely 
prickly,  so  as  to  ward 
off  the  attacks  of  goats 
and  cattle.  The  bur- 
dock, the  artichoke,  the 
saw  -  wort,  and  the 
globe-thistle  also  be- 
long to  the  same  cen- 
tral division.  Among 
these  earlier  compos- 
ites, however,  there  is 
one  group,  that  of  the 
centauries,  which  leads 
us  gradually  on  to  the 
next  division.  Our  com- 
monest centaury  in 
Britain  (known  to  boys 
as  hardheads)  has  all 
the  florets  equal  and 
similar,  and  looks  in  the  flower  very  much  like  a 
thistle.  But  one  of  its  forms,  and  most  of  the 
cultivated  garden  centauries,  have  the  outer  florets 
much  larger  and  more  broadly  open  than  the  cen- 


FiG.  36, — Flower-head  of  a  thistle, 
consisting  of  very  numerous 
purple  florets,  all  equal  and 
similar. 


HOW  FLOWERS   CLUB  TOGETHER.  145 

tral  ones,  so  that  they  form  an  external  petal-like 
row,  which  adds  greatly  to  the  attractiveness  of 
the  entire  flower-head.  Of  this  type,  the  common 
blue  cornflower  is  a  familiar  example.  Clearly  the 
plant  has  here  developed  the  outer  florets  more 
than  the  inner  ones  in  order  to  make  them  act  as 
extra  special  attractions  to  the  insect  fertilisers. 

The  more  familiar  type  of  composites  so  much 
cultivated  in  gardens  carries  these  tactics  a  step 
further.  We  saw  reason  to  believe  in  a  previous 
chapter  that  petals  were  originally  stamens,  flat- 
tened and  brightly  coloured,  and  told  off  for  the 
special  attractive  function.  Just  in  the  same  way 
the  ray-florets  of  the  daisy,  the  sunflower,  the 
single  dahlia,  and  the  aster  are  florets  which  have 
been  flattened  and  partially  or  wholly  sterilised 
in  order  to  act  as  allurements  to  insects.  The 
ray-floret  acts  for  the  compound  flower-head  as 
the  petal  acts  for  the  individual  blossom. 

In  many  other  families  of  plants  besides  the 
composites  we  get  foreshadowings,  so  to  speak,  of 
this  mode  of  procedure.  The  outer  flowers  of.  a 
cluster,  be  it  head  or  umbel,  are  often  rendered 
larger  so  as  to  increase  the  effective  attractive- 
ness of  the  whole ;  and  sometimes  they  are  sacri- 
ficed to  the  inner  ones  by  being  made  neuter  or 
sterile,  that  is  to  say,  being  deprived  of  stamens 
and  pistil.  Thus  in  cow-parsnip,  which  is  a  mem- 
ber of  the  same  family  as  the  carrot  and  the  hem- 
lock, the  outer  flowers  of  each  umbel  are  much 
larger  than  the  central  ones,  while  in  the  wild 
guelder-rose  the  central  flowers  alone  are  fertile, 
the  outer  ones  being  converted  into  mere  ex- 
panded white  corollas  with  no  essential  floral 
organs.  But  it  is  the  composites  that  have  car- 
ried this  process  of  division  of  labour  furthest, 
10 


146  THE    STORY   OF   THE   PLANTS. 

by  making  the  ray-florets  into  mere  petal-like 
straps,  which  do  no  work  themselves,  but  simply 
serve  to  attract  the  fertilising  insects  to  the  com- 
pound flower-head. 

An  immense  number  of  these  composites  with 
flattened  ray-florets  grow  in  our  fields  or  are  cul- 
tivated in  our  gardens.  In  the  simpler  among 
them,  such  as  the  sunflower,  the  corn-marigold, 
the  ragwort,  and  the  golden-rod,  both  ray-florets 
and  central  florets  are  simply  yellow.  But  in 
others,  such  as  the  daisy,  the  ox-eye  daisy,  the 
aster,  and  the  camomile,  the  ray-florets  differ  in 
colour  from  those  of  the  centre ;  the  latter  re- 
main yellow,  while  the  former  become  white,  or 
are  tinged  with  pink,  or  even  flaunt  forth  in  scar- 
let, crimson,  blue,  or  purple.  Of  this  class  one 
may  mention  as  familiar  instances  the  dahlia,  the 
zinnia,  the  Michaelmas  daisies,  the  cinerarias,  and 
the  pretty  coreopsis  so  common  in  our  gardens. 
Gardeners,  however,  are  not  content  to  let  us  ad- 
mire these  flowers  as  nature  made  them.  They 
generally  "  double  "  them — that  is  to  say,  by  care- 
fully selecting  certain  natural  varieties,  they  pro- 
duce a  form  in  which  all  the  florets  have  at  last 
become  neutral  and  strap-shaped.  This  is  well 
seen  in  the  garden  chrysanthemum,  where,  how- 
ever, if  you  open  the  very  centre  of  the  doubled 
flower-head,  you  will  generally  find  in  its  midst 
a  few  remaining  fertile  tubular  blossoms.  The 
same  process  is  also  well  seen  in  the  various 
stages  between  the  single  and  the  double  dahlia. 
Such  ^'  double "  composites  can  set  little  or  no 
seed,  and  are  therefore  from  the  point  of  view  of 
the  plant  mere  abortions.  Nor  are  they  beauti- 
ful to  an  eye  accustomed  to  the  ground  plan  of 
floral   architecture.     Remember,   of  course,   that 


HOW   FLOWERS   CLUB   TOGETHER.  147 

what  we  call  "  a  double  flower  "  in  a  rose,  a  but- 
tercup, or  any  other  simple  blossom  is  one  in 
which  the  stamens  have  been  converted  into  super- 
numerary and  useless  petals;  while  in  a  composite 
it  is  a  flower-head  in  which  the  central  florets 
have  been  converted  into  barren  ray-florets.  In 
either  case,  however,  the  result  is  the  same — the 
flowers  are  rendered  abortive  and  sterile. 

Nature's  way  is  quite  different.  Here  is  how 
she  manages  the  fertilisation  of  one  of  these  ray- 
bearing  composites — say  for  example  the  sun- 
flower, where  the  individual  florets  are  quite  big 
enough  to  enable  one  to  follow  the  process  with 
the  naked  eye.  The  large  yellow  rays  act  as  ad- 
vertisements ;  the  bee,  attracted  by  them,  settles 
on  the  outer  edge  and  fertilises  the  flowers  from 
without  inward.  To  meet  this  habit  of  his,  the 
florets  of  the  sunflower  pass  through  four  regu- 
lar stages.  They  open  from  without  inward.  In 
the  centre  are  unopened  buds.  Next  come  open 
flowers,  in  which  the  stamens  are  shedding  their 
pollen,  while  the  stigmas  are  still  hidden  within 
the  tube.  Third  in  order,  we  get  florets  in  which 
the  stamens  have  withered,  while  the  stigmas  have 
now  ripened  and  opened.  Last  of  all,  we  get, 
next  to  the  rays,  a  set  of  overblown  florets,  en- 
gaged in  maturing  their  fertilised  fruits.  The 
bee  thus  comes  first  to  the  florets  in  the  female 
stage,  which  he  fertilises  with  pollen  from  the 
last  plant  he  visited ;  he  then  goes  on  to  florets 
in  the  male  stage,  where  he  collects  more  pollen 
for  the  next  plant  to  which  he  chooses  to  devote 
his  attention.  The  florets  of  the  sunflower  are 
interesting  also  for  the  fact  that,  unlike  most 
composites,  they  still  retain  obvious  traces  of  a 
true  calyx. 


148  THE   STORY   OF  THE   PLANTS. 

The  composites  which  produce  purple  or  blue 
ray-florets  to  attract  insects  are  in  some  ways  the 
highest  of  their  class.  Still,  there  is  another  group 
of  composites  which  has  proceeded  a  little  further 
in  one  direction  ;  and  that  is  the  group  which  in- 
cludes the  dandelions.  In  these  heads  all  the 
florets  alike  have  become  strap-shaped  or  ray- 
like ;  but  they  differ  from  the  double  composites 
of  the  gardeners  in  this,  that  each  floret  still  re- 
tains its  stamens  and  pistil.  The  composites  of 
the  dandelion  group  are  chiefly  weeds  like  the 
hawkbit  and  the  sow-thistle.  A  few  are  cultivated 
as  vegetables,  such  as  lettuce,  salsify,  chicory, 
and  endive  ;  fewer  still  are  prized  for  their  flow- 
ers for  ornamental  purposes,  such  as  the  orange 
hawkweed.  The  prevailing  colour  in  this  class  is 
yellow,  and  the  devices  for  insect-fertilisation  are 
not  nearly  so  high  as  in  the  ray-bearing  group. 
I  regard  them  as  to  a  great  extent  a  retrograde 
tribe  of  the  composite  family. 

In  this  chapter  I  have  dealt  chiefly  with  the 
co-operative  clubbing  together  of  insect-fertilised 
flowers,  for  purposes  of  mutual  convenience;  but 
you  must  not  forget  that  similar  clubs  exist  also 
among  the  wind-fertilised  blossoms  in  quite  equal 
profusion.  Such  are  the  catkins  of  forest  trees, 
the  panicles  of  grasses,  the  spikes  of  sedges,  and 
the  heads  of  the  black-cap  rush  and  many  other 
water-plants.  Some  of  these,  such  as  the  bur- 
reed,  we  have  already  considered. 

Lastly,  I  ought  to  add  that  where  the  flowers 
themselves  are  inconspicuous,  attention  is  often 
called  to  them  by  a  bright-coloured  leaf  or  group 
of  leaves  in  their  immediate  neighbourhood.  We 
saw  an  instance  of  this  in  the  great  white  spathe 
or  folding  leaf  which  encloses  the  male  and  female 


WHAT   PLANTS   DO   FOR  THEIR  YOUNG.       149 

flowers  of  the  "  calla  lily."  In  the  greenhouse 
poinsettia  the  individual  flowers  are  tiny  and  un- 
noticeable ;  but  they  are  rich  in  honey,  and  round 
them  has  been  developed  a  great  bunch  of  bril- 
liant scarlet  leaves  which  renders  them  among 
the  most  decorative  objects  in  nature.  A  laven- 
der that  grows  in  Southern  Europe  has  dusky 
brown  flowers ;  but  the  bunch  is  crowned  by  a 
number  of  mauve  or  lilac  leaves,  hung  out  like 
flags  to  attract  the  insects.  A  scarlet  salvia  much 
grown  in  windows  similarly  supplements  its  rather 
handsome  flowers  by  much  handsomer  calyxes 
and  bracts  which  make  it  a  perfect  blaze  of  splen- 
did colour.  It  doesn't  matter  to  the  plant  how  it 
produces  its  effect ;  all  it  cares  for  is  that  by  hook 
or  by  crook  it  should  attract  its  insects  and  get 
itself  fertilised. 


CHAPTER   XI. 

WHAT    PLANTS    DO    FOR    THEIR    YOUNG. 

After  the  flower  is  fertilised  it  has  to  set  its 
seed.  And  after  the  seed  is  set  the  plant  has  to 
sow  and  disperse  it. 

Now,  the  fruit  and  seed  form  the  most  difficult 
part  of  technical  botany,  and  I  will  not  apologise 
for  treating  them  here  a  little  cavalierly.  I  will 
tell  you  no  more  about  them  than  it  is  actually 
necessary  you  should  know,  leaving  you  to  pur- 
sue the  subject  if  you  will  in  more  formal  treatises. 

The  pistil,  after  it  has  been  fertilised  and  ar- 
rived at  maturity,  is  called  the  fruit.  In  flowers 
like  the  buttercup,  where  there  are  many  carpels, 
the  fruit  consists  of  distinct  parts,  each  one-seeded 


150  THE   STORY  OF  THE   PLANTS. 

little  nuts  in  the  meadow  buttercup,  but  many- 
seeded  pods  in  the  marsh-marigold  and  the  lark- 
spur. Where  the  carpels  have  combined  into  a 
single  ovary,  we  get  a  many-chambered  fruit,  as 
in  the  poppy,  which  consists,  when  cut  across,  of 
ten  seed-bearing  chambers.  Most  fruits  are  dry 
capsules  or  pods,  either  single,  as  in  the  pea,  the 
bean,  the  vetch,  and  the  laburnum  ;  or  double,  as 
in  the  wallflower  and  shepherd's-purse ;  or  many- 
chambered,  as  in  the  lily,  the  wild  hyacinth,  the 
poppy,  the  campion.  As  a  rule  the  fruit  consists 
of  as  many  carpels  or  as  many  chambers  as  the 
unfertilised  ovary. 

Fruits  are  often  dispersed  entire,  and  this  is 
especially  true  when  they  contain  only  one  or 
two  seeds.  In  such  instances  they  sometimes  fall 
on  the  ground  direct,  as  is  the  case  with  most 
nuts  ;  or  else  they  have  wings  or  parachutes  which 
enable  the  wind  to  seize  them,  and  carry  them 
to  a  distance,  where  they  can  alight  on  unex- 
hausted soil,  far  away  from  the  roots  of  the 
mother  plant.  Such  fruits  are  common  among 
forest  trees.  The  maples,  for  example,  have  a 
double  fruit,  often  called  a  key^  which  the  wind 
whirls  away  as  soon  as  the  seeds  are  ready  for 
dispersion  (Figs.  37,  38,  39,  40,  41).  In  the  lime, 
the  common  stalk  of  the  flowers  is  winged  by  a 
thin  leaf;  and  when  the  little  nuts  are  ripe  the 
wind  detaches  them  and  carries  them  away  by 
means  of  this  joint  parachute.  In  the  birch,  elm, 
and  ash  the  fruit  is  a  one-seeded  nut,  with  its  edge 
produced  into  a  leathery  or  papery  wing,  which 
serves  to  float  it. 

But  more  often  the  fruit  at  maturity  opens 
and  scatters  its  seeds,  as  we  see  in  the  pea,  the 
wild  hyacinth,  and  the  iris.     Sometimes  the  seeds 


WHAT   PLANTS   DO   FOR  THEIR  YOUNG.       151 


SO  released  merely  drop  upon  the  ground,  but 
most  often  some  device  exists  for  scattering  them 
distance,  so  as  to  obtain  the  advantage  of 


to  a 


unexhausted  soil  for  the  young  seedling.     Thus 


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most  capsules  open  at  the  top,  so  that  the  seeds, 
can  only  drop  out  when  the  wind  is  high  enough 
to  carry  them  to  some  distance.     In  the  poppy- 


152  THE   STORY   OF  THE   PLANTS. 

head  the  capsule  opens  by  pores  at  the  side,  and, 
if  you  shake  one  as  it  grows,  you  will  find  it  takes 
a  considerable  shaking  to  dislodge  the  seeds  from 
the  walls  of  their  chamber.  Thus  only  in  high 
winds  are  the  poppy  seeds  dispersed.  In  the 
mouse-ear  chickweed  the  capsule  is  directed 
slightly  upward  at  the  end  for  a  similar  purpose. 
Sometimes,  again,  the  valves  of  the  fruit  open 
elastically  and  shoot  out  the  seeds;  this  device  is 
familiarly  known  in  the  garden  balsam,  and  it 
occurs  also  in  the  little  English  wallcress.  The 
sandbox-tree  of  the  West  Indies  has  a  large  round 
woody  capsule,  which  bursts  with  a  report  like  a 
pistol,  and  scatters  its  seeds  with  such  violence  as 
to  inflict  a  severe  wound  upon  anybody  who  hap- 
pens to  be  struck  by  them. 

Where  seeds  are  numerous,  they  are  oftenest 
dispersed  in  some  such  manner,  by  the  capsule 
opening  naturally  and  scattering  its  contents; 
but  where  they  are  few  in  number,  it  more  fre- 
quently happens  that  the  fruit  does  not  open,  as 
in  the  oak  or  the  elm;  and  when  there  is  only  one 
seed,  the  fruit  and  seed  become  almost  indistin- 
guishable, and  are  popularly  regarded  as  a  seed 
only.  For  example,  in  the  pea,  we  distinguish  at 
once  between  the  pod,  which  is  a  fruit  containing 
many  seeds,  and  the  pea  which  is  one  such  seed 
among  the  many ;  but  in  wheat  or  oats  the  fruit 
is  small  and  one-seeded,  and  its  covering  is  so 
closely  united  with  the  seed  as  to  be  practically 
inseparable.  Fruits  like  these  do  not  open,  and 
are  dispersed  whole.  The  fruits  of  most  compos- 
ites are  crowned  by  the  feather-like  hairs  which 
represent  the  calyx,  and  float  on  the  breeze  as 
thistledown  or  dandelion  clocks  (Figs.  42,  43,  44, 
45).     John-go-to-bed-at-noon,  an  English  compos- 


WHAT   PLANTS   DO   FOR   THEIR  YOUNG. 


53 


ite  of  the  dandelion  type,  has  a  very  remarkable 
and  highly-developed  parachute  of  this  descrip- 
tion. In  the  anemones  and  clematis  the  fruit 
consists  of   several    distinct    one-seeded   carpels, 


each  furnished  with  a  long  feathery  awn  for  the 
purpose  of  floating ;  our  common  English  clematis 
or  traveller's  joy,  when  in  the  fruiting  condition, 
is  known  on  this  account  as  "old  man's  beard." 
Floating  fruits  like  these,  or  those  of  many  sedges 


154  THE   STORY   OF  THE   PLANTS.  ^ 

and  grasses,  will  often  be  carried  by  the  wind  for 
miles  together.  A  well-known  example  of  this 
type  is  the  sedge  commonly  though  wrongly  de- 
scribed as  cotton-grass. 

In  other  instances  it  is  the  seed,  not  the  fruit, 
that  is  winged  or  feathered.  The  pod  of  the  wil- 
low opens  at  maturity,  and  allows  a  large  number 
of  cottony  seeds  to  escape  upon  the  breeze.  The 
same  thing  happens  in  the  beautiful  rose-bay  and 
the  other  willow-herbs.  Cotton  is  composed  of 
the  similar  floating  hairs  attached  to  the  seeds  of 
a  sub-tropical  mallow-like  tree. 

You  will  have  observed,  however,  that  not  one 
of  the  fruits  which  I  have  hitherto  mentioned  is  a 
fruit  at  all  in  the  common  or  popular  acceptation 
of  the  word.  They  are  only  at  best  what  most 
people  call  pods  or  capsules.  A  true  fruit,  as  most 
people  think  of  it,  is  coloured,  juicy,  pulpy,  sweet, 
and  edible.  How  did  such  fruits  come  into  exist- 
ence, and  what  is  the  use  of  them? 

Well,  just  as  certain  plants  desire  to  attract 
insects  to  fertilise  their  flowers,  so  do  other  plants 
desire  to  attract  birds  and  beasts  to  disseminate 
their  fruits  for  them.  If  any  fruit  happened  to 
possess  a  coloured  and  juicy  outer  coat,  or  to  show 
any  tendency  towards  the  production  of  such  a 
coat,  it  would  sooner  or  later  be  eaten  by  animals. 
If  the  animal  digested  the  actual  seed,  however, 
so  much  the  worse  for  the  plant,  and  we  shall  see 
by  and  by  that  most  plants  take  great  care  to 
prevent  their  true  seeds  being  eaten  and  assimi- 
lated by  animals.  But  if  the  seed  was  very  small 
and  tough,  or  had  a  stony  covering,  it  would  either 
be  passed  through  the  animal's  body  undigested, 
or  else  thrown  away  by  him  when  he  had  finished 


WHAT   PLANTS   DO   FOR  THEIR  YOUNG.       1 55 

eating  the  pulpy  exterior.  So,  many  plants  have 
acquired  fruits  of  this  description — edible  fruits, 
intended  for  the  attraction  of  birds  and  animals. 
As  a  rule  the  animals  disperse  the  seeds  in  the 
well-manured  soil  near  their  own  nests  or  lairs, 
so  that  the  young  plants  produced  from  such  fruits 
start  in  life  under  exceptional  advantages. 

Fruits  that  seek  to  attract  animals  use  much 
the  same  baits  to  allure  them  in  the  way  of  colour 
and  sweet  taste  as  do  the  flowers  that  seek  to  at- 
tract insects.  But  just  as  almost  any  part  of  the 
flower  may  be  brightly  coloured,  so  almost  any 
part  of  the  fruit  may  be  sweet  and  pulpy.  Thus 
we  get  an  astonishing  and  rather  embarrassing 
variety  of  special  devices  in  this  matter. 

A  few  instances  must  suffice  us.  In  the  rasp- 
berry and  blackberry  the  fruit  consists  of  sepa- 
rate carpels,  in  each  of  which  the  outer  coat  be- 
comes soft  and  sweet,  while  the  actual  seed  is 
hard  and  nut-like.  In  the  one  case  the  fruit  is 
red,  in  the  other  black,  but  very  conspicuous 
among  the  green  leaves  in  autumn.  These  ber- 
ries are  eaten  by  birds,  and  their  seeds  are  dis- 
persed in  copse  or  hedgerow.  But  in  the  straw- 
berry, which  ']&  a  near  relation  of  both,  with  a  very 
similar  flower,  the  actual  carpels  remain  to  the  end 
quite  small  and  seed-like;  they  are  the  tiny  hard 
objects  scattered  about  in  pits  like  miniature  nuts 
over  the  surface  of  the  ripe  berry.  Here  it  is  the 
common  receptacle  of  the  fruit  that  swells  out 
and  reddens,  the  part  answering  to  the  central 
piece  which  comes  out  whole  in  the  middle  of  the 
raspberry ;  so  that  what  we  eat  in  the  one  fruit  is 
the  very  same  part  as  what  we  throw  away  in  the 
other.  In  the  plum,  the  cherry,  and  the  peach, 
on  the  other  hand,  there  is  but  one  carpel,  and  its 


156  THE    STORY   OF  THE   PLANTS. 

outer  covering  grows  soft,  sweet,  and  brightly  col- 
oured ;  while  the  actual  seed,  though  soft,  is  con- 
tained in  a  hard  and  stony  jacket,  an  inner  layer  of 
the  fruit  coat.  Here  the  true  seed  is  what  we  call 
the  kernel,  but  it  is  amply  protected  by  its  bone- 
like coverlet.  In  the  apple  and  pear  the  ovary  is 
inferior;  the  fruit  is  thus  crowned  by  the  remains 
of  the  calyx  ;  if  you  cut  it  across  you  will  find  it 
consists  of  a  fleshy  part,  which  is  the  swollen  stem, 
enclosing  the  true  fruit  or  core,  with  a  number  of 
seeds  which  we  call  the  pips.  All  these  fruits  be- 
long to  the  family  of  the  roses ;  they  serve  to  show 
the  immense  variety  of  plan  and  structure  which 
occurs  even  in  closely  related  species.  Other  suc- 
culent fruits  of  the  same  family  are  the  rose-hip, 
the  haw,  the  medlar,  and  the  nectarine. 

Among  familiar  woodland  fruits  dispersed  by 
birds  I  may  mention  the  elderberry,  the  dogwood, 
the  honeysuckle,  the  whortleberry,  the  holly,  the 
cuckoo-pint,  the  barberry,  and  the  spindle-tree. 
The  white  berries  of  the  mistletoe,  which  is  a 
parasitic  plant,  are  eaten  by  the  missel-thrush,  a 
bird  who  has  a  special  affection  for  this  particu- 
lar food.  But  they  are  very  sticky,  and  the  seeds 
therefore  adhere  to  the  bird's  beak  and  feet.  To 
get  rid  of  them,  he  rubs  them  off  on  the  fork  of  a 
poplar  branch,  or  in  the  bark  of  an  apple-tree, 
which  are  the  exact  places  where  the  mistletoe 
most  desires  to  place  itself.  Many  such  close 
correspondences  between  bird  and  fruit  exist  in 
nature. 

Our  northern  berries  are  chiefly  designed  to  be 
eaten  by  small  birds  like  robins  and  hawfinches. 
But  in  southern  climates  larger  fruits  exist, 
adapted  to  the  tastes  of  larger  animals  such  as 
parrots,  toucans,  hornbills,  fruit-bats,  and  mon- 


WHAT   PLANTS   DO   FOR   THEIR  YOUNG.       157 


keys.  Our  own  small  kinds  can  generally  be 
eaten  whole,  like  the  currant  and  the  strawberry; 
but  these  large  southern  fruits  have  often  a  bitter 
or  unpleasant  or  very  thick  rind,  which  the  birds 
or  monkeys,  for  whose  use  they  are  intended, 
know  how  to  strip  off  them.  Cases  in  point  are 
the  orange,  the  lemon,  the  shaddock,  the  banana, 
the  pine-apple,  the  mango,  the  custard-apple,  and 
the  breadfruit.     The  melon,  cucumber,  pumpkin, 


Fig.  46. 

Adhesive  fruits. 


Fig.  47. 


Fig.  48. 


Fig.  46,  of  houndstongue.     Fig.  47,  of  cleavers. 
Fig.  48,  of  herb-bennet. 


gourd,  vegetable  marrow,  and  water-melon  are 
other  southern  forms  cultivated  in  the  north  for 
the  sake  of  their  fruits.  In  the  pomegranate  the 
fruit  itself  is  a  dry  capsule,  but  the  seeds  are  each 
enclosed  in  a  separate  juicy  coat.  The  grape  is 
a  fruit  too  well  known  to  require  detailed  de- 
scription. 

As  flowers  sometimes  club  together,  so  also  do 
fruits.  In  the  mulberry  the  apparent  berry  is 
really  made  up  of  the  distinct  carpels  of  several 
separate   flowers,   which    grow  together   as   they 


158  THE   STORY   OF   THE   PLANTS. 

ripen;  while  the  fig  is  a  hollow  stalk,  in  which 
numerous  tiny  fruits,  commonl}'  called  seeds,  are 
closely  embedded. 

In  all  these  cases  animals  act  as  willing  agents 
in  the  dispersal  of  fruits  or  seeds.  But  some- 
times the  plant  compels  them  to  carry  its  seeds 
against  their  will.  Thus  the  fruits  of  the  hounds- 
tongue  (Fig.  46)  consist  of  four  small  nuts,  covered 
with  hook-like  prickles,  which  cling  to  the  coats 
of  sheep  or  cattle.  The  beasts  rub  these  annoy- 
ing burdens  off  against  bushes  or  hedges,  and  so 
disseminate  the  seeds  in  suitable  places  for  ger- 
mination. The  double  fruit  of  cleavers  (Fig.  47) 
is  also  supplied  with  similar  prickles,  while  that 
of  herb-bennet  (Fig.  48)  has  a  long  curved  awn 
which  makes  it  catch  at  once  on  any  passing 
animal. 

There  are  a  large  number  of  fruits,  however, 
with  richly  stored  seeds,  which  desire  rather  to 
escape  the  notice  of  animals,  some  of  whom,  like 
squirrels  and  dormice,  try  to  make  their  living 
out  of  them.  These  we  call  nuts.  Their  tactics 
are  the  exact  opposite  of  those  pursued  by  the 
edible  fruits.  For  the  edible  fruits  strive  to 
attract  animals  to  disperse  them;  the  nuts,  on 
the  contrary,  having  the  actual  seed  richly  stored 
with  oils  and  starches,  desire  to  protect  it  from 
being  eaten  and  destroyed.  Hence  they  are 
generally  green  when  on  the  tree,  so  as  to 
escape  notice,  and  brown  when  lying  on  the 
ground  beneath  it.  Cases  of  these  protectively- 
arranged  fruits,  with  hard  shells  and  often  with 
nauseous  external  coverings  (some  of  which  are 
not  regarded  as  nuts  in  the  strict  botanical 
sense),  are  the  walnut,  the  hazel-nut,  the  coco- 


WHAT   PLANTS   DO   FOR  THEIR  YOUNG.       159 

nut,  the  chestnut,  the  acorn,  the  lime-nut,  the 
almond,  and  the  hickory-nut.  In  the  Brazil  nut 
the  seeds  (which  are  what  we  commonly  call  the 
nuts)  are  enclosed  in  a  solid  shell  like  that  of  a 
coco-nut,  and  are  themselves  also  hard  and  nut- 
like. In  the  chestnut  the  fruit  is  a  prickly  cap- 
sule, inside  which  lie  the  seeds,  which  we  know 
as  chestnuts. 

But  why  have  some  plants  so  many  seeds  and 
some  so  few  ?  Well,  the  simpler  and  earlier 
types  produce  a  very  large  number  of  ill-pro- 
vided seeds,  which  they  turn  loose  upon  the 
world  to  shift  for  themselves  almost  from  the 
outset.  Many  of  them  perish,  but  a  few  survive. 
On  the  other  hand,  the  more  advanced  plants, 
as  a  rule,  produce  only  a  small  number  of  seeds, 
but  each  of  these  is  well  provided  with  starches 
and  oils  for  the  growth  of  the  young  plant ;  and 
as  most  such  survive,  any  tendency  in  the  direc- 
tion of  laying  by  food-stuffs  would  of  course  be 
favoured  by  natural  selection.  Just  so  among 
animals,  a  codfish  produces  nearly  a  million  eggs, 
of  which  only  two  or  three  on  an  average  survive 
to  maturity  ;  while  a  bird  produces  half  a  dozen 
large  and  well-stored  eggs,  and  a  cow  or  a  horse 
rarely  brings  forth  more  than  one  calf  or  foal  at 
a  birth.  Decrease  in  the  number  of  seeds  is  a  fair 
rough  test  of  relative  progress. 

In  nuts,  you  can  see  at  once,  the  seeds  are 
very  richly  stored,  and  the  young  plant  starts  in 
life,  able  to  draw  for  a  time  on  these  ready-made 
food-stuffs,  until  its  green  leaves  are  in  a  position 
to  lay  by  starches  and  protoplasm  in  plenty  for 
it.  It  draws  by  degrees  upon  the  accumulated 
materials.     Such   plants  are   like   capitalists  who 


l6o  THE   STORY   OF  THE   PLANTS. 

can  start  their  sons  well  in  life  with  a  good  be- 
ginning. On  the  other  hand,  the  poppy  has  to 
set  out  on  its  career  with  a  very  poor  equipment ; 
it  must  begin  picking  up  carbonic  acid  for  itself 
almost  from  the  outset.  Such  plants  are  like 
street  arabs,  compelled  to  shift  as  best  they  can 
from  their  earliest  days.  A  coco-nut  starts  so 
well  that  the  young  palm  can  grow  to  a  consider- 
able size  without  working  for  itself;  so  to  a  less 
degree  do  walnuts,  hazels,  and  oak-trees.  Among 
other  sets  of  plants  there  are  tw^o  great  groups 
which  have  especially  learned  to  lay  by  foods  for 
their  seedlings — the  peaflower  family  and  the 
grasses.  In  both  these  cases  the  young  plants 
start  in  life  with  exceptional  advantages.  But 
what  will  feed  a  young  plant  will  also  feed  an 
animal.  Hence  men  live  largely  in  different 
countries  off  such  richly-stored  seeds — among 
nuts,  the  coco-nut,  the  chestnut,  and  the  walnut ; 
among  peaflower  seeds,  the  pea,  the  bean,  the 
vetch,  the  lentil  ;  among  grasses,  wheat,  rice, 
barley,  Indian  corn,  rye,  millet. 

Recollect,  however,  that  in  all  these  cases  the 
plant  does  not  desire  the  seed  to  be  eaten.  It 
stored  the  tissues  richly  for  its  own  sake  and  its 
offspring's  alone,  and  we  come  and  rob  it.  So, 
too,  with  the  edible  roots  or  tubers,  such  as 
potatoes,  yams,  turnips,  beet-root,  and  so  forth ; 
the  plant  meant  to  use  them  for  its  own  future 
growth  ;  man  appropriates  them  and  disappoints 
its  natural  expectations.  It  is  quite  different 
with  the  succulent  fruits,  like  the  date  and  the 
plantain,  which  form  in  many  countries  the  staple 
food  of  great  populations  ;  nature  meant  those  to 
be  eaten  by  animals,  and  offered  the  pulp  in  re- 
turn for  the  benefit  of  dispersion. 


THE   STEM    AND    BRANCHES.  l6l 

Finally,  when  the  seed  is  put  into  the  ground 
and  exposed  to  warmth  and  moisture,  it  begins  to 
germinate.  This  it  does  by  sending  up  a  small 
growing  shoot  towards  the  light,  which  soon  de- 
velops green  leaves;  as  well  as  by  sending  down 
a  root  towards  the  earth,  which  soon  begins  to 
suck  up  water,  together  with  the  dissolved  nitroge- 
nous matter.  That  is  the  beginning  of  a  fresh 
plant-colony,  which  thus  owes  its  existence  to  two 
separate  individuals,  a  father  and  a  mother.  The 
seed  consists  of  two  first  seed-leaves  in  the  five- 
fold plants,  as  you  can  see  very  well  in  a  sprout- 
ing bean,  and  of  one  such  seed-leaf  in  the  three- 
fold division,  as  you  can  see  very  well  in  a  sprout- 
ing grain  of  wheat,  or,  still  better,  a  lily  seed. 
These  earliest  leaves  are  technically  known  as 
seed-leaves  or  cotyIedo?is^  and  that  is  why  the  five- 
fold plants  are  known  to  botanists  by  the  awk- 
ward name  of  dicotyledojis,  while  the  threefold  are 
called  JHonocotyledons.  These  names  mean  merely 
plants  with  two  or  with  one  seed-leaf. 


CHAPTER   XII. 

THE    STEM    AND    BRANCHES. 

You  may  have  observed  that  so  far  I  have 
told  you  a  good  deal  about  leaves  and  roots,  flow- 
ers and  seeds,  but  little  or  nothing  about  the  na- 
ture of  the  stems  and  branches  that  bear  them. 
I  have  done  this  on  purpose;  for  my  object  has 
been  to  give  you  as  much  information  at  a  time 
as  you  could  then  and  there  understand,  building 
up  by  degrees  your  conception  of  plant  economy. 
II 


l62  THE   STORY   OF  THE   PLANTS. 

Now,  leaves  and  flowers  are,  so  to  speak,  the  units 
of  the  plant-colony,  while  stem  and  branches  are 
the  community  as  a  whole  and  the  mode  of  its 
organisation.  You  must  know  something  about 
the  component  parts  before  you  can  get  to  under- 
stand the  whole  built  up  of  them  ;  you  must  have 
seen  the  individual  citizens  themselves  before  you 
can  comprehend  the  city  or  nation  composed  by 
their  union. 

The  stem,  then,  is  the  part  of  the  plant-colony 
which  does  not  consist  of  individual  leaves,  either 
digestive  or  floral,  but  which  binds  them  all  to- 
gether, raises  them  visibly  to  the  air,  and  supplies 
them  with  water,  nitrogenous  matter,  and  the  re- 
sults of  previous  assimilation  elsewhere.  The 
stem' and  branches  are  common  property,  as  it 
were ;  they  belong  to  the  community  :  they  repre- 
sent the  scaffolding,  the  framework,  the  canals, 
the  roads,  the  streets,  the  sewers,  of  the  com- 
pound plant-colony. 

How  did  stems  begin  to  exist  at  all  ?  The 
most  probable  answer  to  that  question  we  owe, 
not  to  any  professional  botanist,  but  to  our  great 
philosopher,  Mr.  Herbert  Spencer. 

The  simplest  and  earliest  plants,  we  saw,  were 
mere  small  floating  cells,  endowed  with  active 
chlorophyll.  Next  in  the  upward  order  of  evolu- 
tion came  rows  of  such  cells,  arranged  in  long 
lines,  like  hairs  or  threads,  or  like  pearls  in  a  neck- 
lace, as  in  the  green  ooze  of  ponds  and  lakelets. 
Above  these  simple  plants,  again,  come  flat  ex- 
panded collections  of  cells,  as  in  the  fronds  of 
seaweeds.  Now,  all  these  kinds  of  plant  are  stem- 
less.  But  suppose  in  such  a  plant  as  the  last,  one 
frond  or  leaf  took  to  growing  out  of  the  middle 
of  another,  as  it  actually  does  in  many  instances, 


THE  STEM   AND    BRANCHES.  163 

we  should  get  the  beginning  of  a  compound  plant, 
many-leaved,  and  with  a  sort  of  early  or  nascent 
stem,  formed  by  the  part  that  was  common  to 
many  of  the  leaves,  like 
a  midrib.  The  accom- 
panying diagram  (Fig. 
49)  will  make  this  clear- 
er than  any  amount  of 
description  could  pos- 
sibly make  it.  Start- 
ing from  such  a  point, 
certain  plants  would 
soon  find  they  were 
thus  enabled  to  over- 
top others,  and  to  ob- 
tain   freer     access    to   ^._  tt-  .  .       •    .u        1 

,.    ,  ,  ,  1         .  .  .      tiG.  49. — First  steps  in  the  evolu- 

hght  and  carbonic  acid.  tion  of  the  stem. 
Gradually,  natural  se- 
lection would  ensure  that  the  common  central  part 
of  the  growing  plant,  the  developing  stem,  should 
become  harder  and  more  resisting  than  the  rest,  so 
as  to  stand  up  against  the  wind  and  other  oppos- 
ing forces.  At  last  there  would  thus  arise  a 
clearly-marked  trunk,  simple  at  first,  but  later  on 
branching,  which  would  lift  the  leaves  and  flowers 
to  a  considerable  height,  and  hang  them  out  in 
such  a  way  as  to  catch  the  sunlight  and  air  to  the 
best  advantage,  or  to  attract  the  fertilising  insects 
or  court  the  wind  under  the  fairest  conditions.  I 
leave  you  to  think  out  for  yourself  the  various 
stages  of  the  process  by  which  natural  selection 
must  in  the  end  secure  these  desirable  objects. 

In  order  to  understand  the  nature  of  the  stem, 
in  its  fully  developed  form,  however,  we  must  re- 
member that  it  has  three  main  functions.     The 


164  THE    STORY   OF   THE   PLANTS. 

first  is,  to  raise  the  foliage,  with  the  flowers  and 
fruits  as  well,  visibly  above   the   surface   of  the 
ground   on  which  they   grow,  so   that  the  leaves 
may  gain  the  freest  possible  access  to  rays  of  sun- 
light and  to  carbonic  acid,  while  the  flowers  and 
fruit   may   receive   the   attentions   of  insects  and 
birds,  or  other  fertilising  and  distributing  agents. 
The  second  is,  to  conduct  from  the  root  to  the  fo- 
liage and  other   growing  parts  what  is  commonly 
called  the  raw   sap — that   is  to   say,  the  body  of 
water  absorbed  by  the  rootlets,  together  with  the 
nitrogenous  matter  and  food-salts  dissolved  in  it, 
all  of  which   are   needed   for  the  ultimate  manu- 
facture of  protoplasm  and  chlorophyll.    The  third 
is,  to   carry  away  and    distribute  the  various  ma- 
tured   products   of    plant    life,   such   as    starches, 
sugars,   oils,   and    protoplasm,  from  the  places  in 
which   they  are    produced  (such  as  the  leaves)  to 
the  places  where  they  are  needed  for  building  up 
the  various  parts  of  the  compound  organism  (such 
as  the  flowers  and  fruit  or  the  growing  shoots),  as 
well  as  to  the  places  where  such  materials  are  to 
be  stored  up   for  safety  or  for  future  use  (as,  for 
example,  the  tubers  and  roots,  or  the  buds,  bulbs, 
and  other  dormant  organs).     Each  of  these  three 
essential  functions  we  must  now  proceed  to  con- 
sider separately. 

In  order  to  raise  the  leaves  and  branches  visi- 
bly above  the  ground  into  the  air  above  it,  the 
stem  is  made  much  stronger  and  stouter  than  the 
ordinary  leaf-tissue.  If  the  plant  does  not  rise 
very  high  above  the  ground,  indeed,  as  in  the 
case  of  small  herbs,  and  especially  of  annuals,  its 
stem  need  not  be  very  hard  or  stiff,  and  is  often 
in  point   of  fact  quite  green  and  succulent.     But 


THE   STEM   AND    BRANCHES.  165 

just  in  proportion  as  plants  grow  tall  and  spread- 
ing, carry  masses  of  foliage,  and  are  exposed  to 
heavy  winds,  do  they  need  to  form  a  stout  and 
woody  stem,  which  shall  support  the  constant 
weight  of  the  leaves,  or  even  bear  up  under  the 
load  of  snow  which  may  cover  the  boughs  in  win- 
try weather.  Thus,  a  tapering  tree  like  the  Scotch 
fir  requires  a  comparatively  smaller  stem  than  an 
oak,  because  its  branches  do  not  spread  far  and 
wide,  while  its  single  leaves  are  thin  and  needle- 
like; whereas  the  oak,  with  its  massive  boughs 
extending  far  and  wide  on  every  side,  and  cov- 
ered with  a  weight  of  large  and  expanded  absorb- 
ent leaves,  requires  a  peculiarly  thick  and  but- 
tressed stem  to  support  its  burden.  Both  in  girth 
and  in  texture  it  must  differ  widely  from  the  loose 
and  swaying  pine-tree.  Every  stem  is  thus  a 
piece  of  ingenious  engineering  architecture,  adapt- 
ed on  the  average  to  the  exact  weight  it  will  have 
to  bear,  and  the  exact  strains  of  wind  and  weather 
to  which  on  the  average  it  may  count  upon  being 
exposed  in  the  course  of  its  life-history.  We  see 
the  result  of  occasional  failure  of  adaptation  in 
this  respect  after  every  great  storm,  when  the 
corn  in  the  fields  is  beaten  down  by  hail,  or  the 
fir-trees  in  the  forest  are  snapped  off  short  like 
straw  by  the  force  of  the  tempest.  But  the  sur- 
vivors in  the  long  run  are  those  which  have  suc- 
ceeded best  in  resisting  even  such  unusual  stresses  ; 
and  it  is  they  that  become  the  parents  of  after 
generations,  which  of  course  inherit  their  powers 
of  resistance. 

Most  stems,  at  least  of  perennial  plants,  and 
all  those  of  bushes,  shrubs,  and  forest  trees,  are 
strengthened  for  the  purpose  of  resisting  such 
strains    by    means   of   a   material    which  we  call 


l66  THE   STORY   OF  THE   PLANTS. 

wood.  And  what  is  wood  ?  Well,  it  is  an  ex- 
tremely hard  and  close-grained  tissue,  manufac- 
tured by  the  plant  out  of  its  ordinary  cells  by  a 
deposit  on  their  walls  of  thickening  matter.  This 
process  of  thickening  goes  on  in  each  cell  until 
the  hollow  of  the  centre  is  almost  entirely  filled 
up  by  the  thickening  material,  leaving  only  a 
small  vacant  space  in  the  very  middle.  The 
thickening  matter,  which  consists  for  the  most 
part  of  carbon  and  hydrogen,  is  built  up  there 
by  the  protoplasm  of  the  cell  itself:  but  as  soon 
as  the  process  is  quite  complete,  the  protoplasm 
emigrates  from  the  cell  entirely,  and  goes  to  some 
other  place  where  it  is  more  urgently  needed. 
Thus  wood  is  made  up  of  dead  cells,  whose  walls 
are  immensely  thickened,  but  whose  living  con- 
tents have  migrated  elsewhere. 

In  large  perennial  stems,  like  those  of  oaks 
and  elms,  a  fresh  ring  of  wood  is  added  each 
year  outside  the  ring  of  the  last  growing  season. 
This  new  ring  of  wood  is  interposed  between  the 
bark  (of  which  I  shall  speak  presently)  and  the 
older  wood  of  the  core  or  heart,  which  was  simi- 
larly laid  down  when  the  tree  was  younger.  In 
this  way,  the  number  of  rings,  one  inside  another, 
enables  us  roughly  to  estimate  the  age  of  a  tree 
when  we  cut  it  down  ;  though,  strictly  speaking, 
we  can  only  tell  how  many  times  growth  in  its 
trunk  was  renewed  or  retarded.  Still,  as  a  fair 
general  test,  the  number  of  rings  in  a  trunk  give 
us  an  approximate  idea  of  the  age  of  the  indi- 
vidual tree  that  produced  it. 

The  principle  is  only  true,  however,  of  the 
great  group  of  dicotyledonous  trees,  such  as  beeches 
or  ashes,  as  well  as  of  the  pines  and  other  coni- 
fers.    In  ??wnocotyledonous  trees,  like  the  palms  and 


THE   STEM   AND   BRANCHES.  167 

bamboos,  the  stem  does  not  increase  in  quite  the 
same  way  from  within  outward,  and  there  are 
therefore  no  rings  of  annual  growth  to  judge  by. 
Palms  rise  from  the  ground  as  big  or  nearly  as 
big  at  the  beginning  as  they  will  ever  be  in  the 
end ;  and  though  each  year  they  rise  higher  and 
higher  into  the  air,  and  produce  a  fresh  bunch  of 
leaves  at  their  summit,  they  seldom  branch,  and 
they  never  produce  large  buttressed  stems  like 
the  oak  or  the  chestnut. 

The  second  main  function  of  the  stem  is  to 
convey  the  raw  sap  absorbed  by  the  roots  to  the 
leaves  and  branches,  and  especially  to  the  grow- 
ing points.  This  is  such  a  very  important  element 
in  plant  life  that  we  must  now  consider  it  in  some 
little  detail. 

If  you  look  for  a  moment  at  a  great  spreading 
oak-tree,  with  its  top  rising  forty  or  fifty  feet 
above  the  level  of  the  ground,  and  its  roots 
spreading  as  far  and  as  deep  beneath  the  earth, 
you  will  see  at  once  how  serious  and  difficult  a 
mechanical  problem  it  is  for  the  plant  to  raise 
up  water  from  so  great  a  depth  to  so  great  a 
height  without  the  aid  of  pump  or  siphon.  For 
the  plant  can  no  more  work  miracles  than  you  or 
I  can.  Yet  every  leaf  must  be  constantly  supplied 
with  water,  that  prime  necessary  of  life,  or  it  will 
wither  and  die ;  and  every  growing  part  must  ob- 
tain it  in  abundance,  in  order  to  give  that  plas- 
ticity and  freedom  which  are  needful  for  the  earlier 
constructive  processes.  Protoplasm  itself  can  ef- 
fect nothing  without  the  assistance  of  water  as  a 
solvent  for  all  materials  it  employs  in  its  opera- 
tions. 

How  does  the  plant  get  over  these  difficulties  ? 


1 68       THE  STORY  OF  THE  PLANTS. 

Well,  the  stem  is  well  provided  with  a  whole  sys- 
tem of  upward  distributing  vessels  in  which  water 
may  be  conveyed  to  the  various  parts,  just  as 
it  is  conveyed  in  towns  through  the  pipes  and  taps 
wherever  it  is  needed.  But  what  is  the  motive 
power  for  this  mechanical  work  ?  How  does  the 
plant  raise  so  much  liquid  to  such  a  considerable 
height,  without  the  intervention  of  any  visible 
and  tangible  machinery  ? 

Two  main  agents  are  employed  for  this  pur- 
pose. The  one  is  known  as  root-pressure ;  the 
other  as  evaporation. 

I  begin  with  the  former.  The  cells  of  which 
roots  are  made  up  are  most  ingeniously  constructed 
so  as  to  exert  this  peculiar  form  of  pressure. 
Each  one  of  them  has  at  its  outer  or  free  end, 
where  it  comes  into  contact  with  the  moist  earth, 
a  wall  of  such  a  nature  that  it  very  readily  ab- 
sorbs water,  and  allows  the  water  so  absorbed  to 
flow  freely  through  it  inward.  But  once  in,  the 
water  seems  almost  as  if  imprisoned  in  a  pump; 
it  cannot  pass  outward  again,  only  inward  and 
upward.  You  may  compare  the  cell  in  this  respect 
with  those  mechanical  valves  which  yield  readily 
to  the  pressure  of  fluids  from  outside,  but  instantly 
close  when  a  fluid  from  inside  attempts  to  pass 
through  them.  In  this  way  the  outer  cells  of  the 
hairs  on  the  roots,  which  come  in  contact  with  the 
moistened  soil,  get  distended  with  water^  and  swell 
and  swell,  till  at  last  their  walls  will  give  no  long- 
er, and  their  own  elasticity  forces  the  water  out 
of  them.  But  the  water  cannot  flow  back  ;  so  it 
has  to  flow  forward.  Again,  each  cell  or  vessel 
which  the  stream  afterwards  enters  is  construct- 
ed on  just  the  same  general  principle  as  the  ab- 
sorbent root-cells  ;  it  allows  water  to  pass  into  it 


THE   STEM   AND    BRANCHES.  1 69 

freely  from  below  upward,  but  does  not  allow  it 
to  pass  back  again  from  above  downward.  Thus 
we  get  a  constant  state  of  what  is  called  turgidity 
in  the  lower  cells;  they  are  as  full  as  they  can 
hold,  and  they  keep  on  contracting  elastically,  so 
as  to  expel  the  water  they  contain  into  other  cells 
next  in  order  above  them.  By  means  of  such 
root-pressure,  as  it  is  called,  raw  sap  is  being  for 
ever  forced  up  from  the  soil  beneath  into  the 
stem  and  branches,  to  supply  the  leaves  with  water 
and  food-salts,  especially  in  early  spring,  when 
the  processes  of  growth  are  most  active  and 
vigorous. 

It  is  owing  to  this  peculiar  property  of  root- 
pressure  that  cut  stems  "bleed"  or  exude  sap, 
especially  in  spring-time.  The  root-pressure  con- 
tinues of  itself  in  spite  of  the  fact  that  the  stem 
has  been  divided ;  and  the  sap  absorbed  by  the 
roots  is  thus  forced  out  at  the  other  end  by  the 
continuous  elasticity  of  the  cells  and  vessels. 
The  fact  that  severed  stems  will  thus  "  bleed  "  or 
exude  raw  sap  shows  in  itself  the  reality  of  root- 
pressure. 

But  root-pressure  alone  would  not  fully  suffice 
to  raise  so  large  a  body  of  water  as  the  plant  re- 
quires to  so  great  a  height  above  the  earth's  sur- 
face. It  is  therefore  largely  supplemented  and 
assisted  by  the  second  or  subsidiary  power  of 
evaporation.  This  evaporation,  or  "  transpira- 
tion "  as  it  is  generally  called,  is  just  as  necessary 
and  essential  to  plants  as  breathing  is  to  men  and 
animals. 

We  must  therefore  enter  a  little  more  fully 
here  into  the  nature  of  so  important  and  universal 
a  plant  function.  You  will  remember  that  when 
we  were  discussing  the  nature  of  leaves;  I  gave 


lyo  THE   STORY   OF  THE   PLANTS. 

you  a  woodcut  of  a  thin  slice  through  a  leaf  (Fig. 
i)  which  showed  the  blade  as  naturally  divided 
into  an  upper  and  under  portion.  The  upper  por- 
tion consisted  of  very  close-set  green  cells,  con- 
taining living  chlorophyll,  and  covered  by  a  single 
transparent  water-layer,  which  absorbed  carbonic 
acid  from  the  air  about,  and  passed  it  on  to  be 
digested  by  the  living  chlorophyll-layer  just  be- 
neath it.  But  the  under  portion  was  sparse-look- 
ing and  spongy ;  it  was  composed  of  cells  loosely 
arranged  among  themselves,  and  interspersed  with 
great  empty  spaces.  I  told  you  but  little  at  the 
time  of  the  function  or  use  of  this  lower  portion  ; 
we  must  return  to  it  now  in  the  present  connec- 
tion, as  a  component  element  in  the  task  of  water- 
supply. 

The  lower  portion  of  most  leaves  is  the  part 
employed  in  the  great  and  necessary  work  of 
evaporation. 

For  this  purpose  the  tissue  at  the  under  side 
of  the  leaf  is  composed  of  loose  and  spongy  cells 
which  have  much  of  their  surface  exposed  to  the 
empty  spaces  between  them :  and  these  emp- 
ty spaces  are  really  air-cavities.  The  object  of 
the  cavities,  indeed,  is  to  facilitate  evaporation. 
Liquid  transpires  into  them  from  the  various  cells 
through  the  wall  that  bounds  them.  How  fast 
water  evaporates  in  the  leaves  of  plants  we  all 
know  by  experience  in  a  thousand  ways.  We 
know,  for  instance,  that  if  we  pick  bunches  of 
flowers  and  leave  them  in  the  sun  without  water, 
they  fade  and  dry  up  in  a  very  short  time.  We 
also  know  that  if  we  forget  to  water  plants  in 
pots,  the  plants  similarly  dry  up  and  die  after  a 
few  hours'  exposure.  Leaves,  in  fact,  are  pur- 
posely arranged  in  most  cases  so  as  to  encourage 


THE   STEM   AND   BRANCHES.  171 

a  very  rapid  evaporation ;  and  evaporation  is  one 
of  their  chief  means  of  raising  water  from  the 
roots  to  the  growing  and  living  portions. 

If  you  examine  the  under  side  of  a  leaf  under 
the  microscope,  you  will  find  it  is  covered  by 
hundreds  of  little  pores  which  look  exactly  like 
mouths,  and  which  are  guarded  by  two  cells  whose 
resemblance  to  lips  is  absurdly  obvious.  These 
pores  are  commonly  known  to  botanists  by  the 
awkward  name  of  stomata,  which  is  the  Greek  for 
mouths;  and  mouths  they  really  are  to  all  exter- 
nal appearance.  You  must  not  suppose,  however, 
that  they  are  truly  mouths  in  the  sense  of  being 
the  organs  with  which  the  plant  eats;  the  upper 
surface  of  the  leaf,  as  we  saw,  with  its  layer  of 
water-cells  and  its  assimilating  chlorophyll-bodies, 
really  answers  in  the  plant  to  our  mouths  and 
stomachs.  The  stomata  or  pores  are  much  more 
like  the  openings  in  the  skin  by  which  we  per- 
spire;  only  perspiration  or  evaporation  is  an  even 
more  important  part  of  life  to  the  plant  than  it  is 
to  the  animal.  Each  of  the  stomata  opens  into  an 
air-cavity;  and  through  it  the  liquid  evaporated 
from  the  cells  passes  out  as  vapour  into  the  open 
air.  Many  leaves  have  thousands  of  such  pores 
on  their  lower  surface;  they  may  easily  be  rec- 
ognised under  the  microscope  by  means  of  the 
curious  guard-cells  which  look  like  lips,  and  which 
give  the  pores,  in  fact,  their  strange  mouth-like 
aspect. 

What  is  the  use  of  these  lips?  Well,  they  are 
employed  for  opening  and  closing  the  evaporat- 
ing pores,  or  stoinata.  In  dry  weather  it  is  not 
desirable  that  the  pores  should  be  open,  for  then 
evaporation  should  be  limited  as  far  as  possible. 
So,  under  these  conditions,  the  lips  contract,  and 


172  THE   STORY  OF  THE   PLANTS. 

the  pore  closes.  Excessive  evaporation  at  such 
times  would,  of  course,  damage  or  destroy  the 
foliage  ;  the  plant  desires  rather  to  store  up  and 
retain  its  stock  of  moisture.  But  after  rain,  and 
in  damp  weather,  the  roots  suck  up  abundant 
water;  and  then  it  becomes  desirable  that  evapo- 
ration should  go  on,  and  the  leaves  and  grow- 
ing shoots  should  be  supplied  with  liquid  food, 
as  well  as  with  the  nitrogenous  matter  and  salts 
dissolved  in  it.  Hence  at  such  times  the  pores 
open  wide,  and  allow  the  water  in  the  form  of 
vapour  to  exude  from  them  freely. 

The  object  of  this  evaporation,  again,  is  two- 
fold. In  the  first  place,  it  supplements  root- 
pressure  as  a.  means  of  raising  water  to  the  leaves 
and  growing  shoots;  and  in  the  second  place,  by 
getting  rid  of  superfluous  liquid,  it  leaves  the 
nitrogenous  material  and  the  food-salts  in  a  more 
concentrated  form,  at  the  very  points  where  they 
are  just  then  needed  for  the  formation  of  fresh  liv- 
ing protoplasm  and  other  useful  constructive  fac- 
tors of  plant-life.  But  how  does  evaporation  raise 
water  from  the  ground  ?  In  this  way.  The  liv- 
ing contents  of  each  cell  on  the  upward  path 
have  a  natural  chemical  affinity  for  water,  and 
will  suck  it  up  greedily  wherever  they  can  get  it. 
Thus  each  part,  as  fast  as  it  loses  water  by 
evaporation,  takes  up  more  water  in  turn  from 
its  next  neighbour  below  ;  and  that  once  more 
withdraws  it  from  the  cell  beneath  it ;  and  so  on 
step  by  step  until  we  reach  the  actual  absorbent 
root-hairs.  Root-pressure  by  itself  could  not 
raise  water  as  high  as  we  often  see  it  raised  in 
great  forest  trees  and  tropical  climbers;  it  has 
not  enough  mechanical  motor  power.  But  here 
evaporation    comes  in,  to   aid  it  in  its  task ;  and 


THE  STEM   AND   BRANCHES.  173 

the  real  motor  power  in  this  last  case  is  the  very 
potent  force  of  chemical  attraction. 

What  I  have  said  here  about  evaporation,  and 
the  way  it  is  conducted  by  means  of  pores  on  the 
surface  of  the  leaves,  is  true  of  the  vast  majority 
of  green  plants  ;  but  considerable  varieties  and 
modifications  occur,  of  course,  in  accordance 
with  the  necessities  of  various  situations.  For 
example,  the  brooms  and  many  other  shrubs  of 
the  same  twiggy  type  have  few  green  leaves,  but 
in  their  stead  produce  lithe  green  stems,  filled 
with  active  chlorophyll.  These  stems  and  branches 
do  all  the  work  usually  performed  by  ordinary 
foliage.  Stems  and  twigs  of  this  type  are  cov- 
ered with  mouth-like  pores,  or  stomata,  in  exactly 
the  same  way  as  the  under  side  of  leaves  in  most 
other  species.  Similarly,  the  very  flattened  leaf- 
like branches  of  the  butcher's  broom,  and  of  the 
Australian  acacias  and  other  Australasian  trees, 
are  well  supplied  with  like  pores  for  purposes  of 
evaporation.  Again,  while  the  pores  are  usually 
found  on  the  under  surface  of  the  leaf,  they  are 
situated  on  the  upper  surface  of  leaves  which  float 
on  water,  like  the  water-lily  and  the  water-crow- 
foot ;  because  in  such  plants  they  would  be  obvi- 
ously useless  for  purposes  of  evaporation  on  the 
lower  side,  which  is  in  contact  with  the  water. 
Some  leaves  have  the  stomata  on  both  sides  alike, 
especially  when  no  one  side  is  much  more  ex- 
posed to  sunlight  than  another.  But  wherever 
they  are  found,  they  always  lie  above  masses  of 
loose  and  spongy  cell-tissue,  in  whose  meshes  and 
air-spaces  evaporation  can  go  on  readily. 

On  the  other  hand,  as  I  noted  before,  leaves 
which  grow  in  very  dry  or  desert  situations  re- 
quire as  much  as  possible  to  curtail  evaporation. 


174  THE   STORY   OF  THE   PLANTS. 

Such  leaves  are  therefore  usually  thick  and  fleshy, 
and  possess  a  very  small  allowance  of  pores.  The 
forms  of  several  leaves,  again,  are  largely  de- 
pendent upon  the  necessity  for  keeping  the  pores 
free  from  wetting,  and  promoting  evaporation 
whenever  it  is  needful  for  the  plant's  health  and 
growth ;  and  this  is  particularly  the  case  with 
what  are  called  "  rolled  leaves,"  such  as  one  sees 
in  the  heaths  and  the  common  rock-roses.  Many 
such  additional  principles  have  always  to  be  taken 
into  consideration  in  attempting  to  account  for 
the  various  shapes  of  foliage:  indeed,  we  can 
only-  rightly  understand  the  form  of  any  given 
leaf  when  we  know  all  about  its  habits  and  its 
native  situation. 

The  stem,  then,  besides  raising  the  leaves  and 
flowers,  for  which  purpose  it  is  often  strengthened 
by  means  of  mechanical  woody  tissue,  also  acts 
as  a  conductor  of  raw  sap  from  the  tips  of  the 
roots  to  the  leaves  and  growing  points,  for  which 
purpose  it  is  further  provided  with  an  elaborate 
system  of  canals  and  vessels,  running  direct  from 
the  absorbent  root  to  all  parts  of  the  compound 
plant  community. 

The  third  function  of  the  stem  and  branches 
is  to  convey  and  distribute  the  elaborated  prod- 
ucts of  plant-chemistry  and  plant-manufacture 
from  the  places  where  they  are  made  to  the 
places  where  they  are  needed  for  practical  pur- 
poses. 

We  saw  long  since  that  starches,  sugars,  pro- 
toplasms, and  chlorophyll  are  manufactured  in 
the  leaves  under  the  influence  of  sunlight;  and 
from  the  materials  so  manufactured  every  part  of 
the  plant  must  ultimately   be  constructed.     But 


THE   STEM   AND    BRANCHES.  1 75 

we  never  said  a  word  at  the  time  about  the  means 
by  which  the  materials  in  question  were  carried 
about  and  distributed  to  the  various  organs  in 
need  of  them.  Nevertheless,  a  moment's  con- 
sideration will  show  you  that  new  leaves  and 
shoots  must  necessarily  be  built  up  at  the  expense 
of  materials  supplied  by  the  older  ones;  that 
flowers,  fruits,  and  seeds  must  be  constructed 
from  protoplasm  handed  over  for  their  use  by  the 
neighbouring  foliage.  Nay  more;  the  root  itself 
grows  and  spreads;  and  the  very  tips  of  the 
roots,  which  themselves  of  course  can  manufac- 
ture nothing,  must  be  supplied  from  above  with 
most  active  and  discriminating  protoplasm,  to 
guide  their  movements.  Whence  do  they  get  it  ? 
From  the  factory  in  the  foliage.  Thus,  from  the 
summit  of  the  tallest  tree  down  to  the  lowest 
root  that  fastens  it  in  the  soil,  there  runs  a  com- 
plex system  of  pipes  and  tubes  for  the  special 
conveyance  of  elaborated  material  ;  and  this  sys- 
tem supplies  every  growing  part  with  the  food- 
stuff necessary  for  its  particular  growth,  and 
every  living  part  with  the  food-stuff  necessary 
for  maintaining  its  life  and  activity.  An  inter- 
change of  protoplasmic  matter,  starches,  and 
sugars,  goes  on  continually  through  the  entire 
organism. 

This  downward  and  outward  stream  of  living 
matter,  carrying  along  with  it  live  protoplasm 
and  other  foods  or  manufactured  materials,  must 
be  carefully  distinguished  from  the  upward  stream 
of  crude  sap  which  rises  from  the  roots  to  the 
leaves  and  branches.  The  one  contains  only  such 
raw  materials  of  life  as  are  supplied  by  the  soil — 
namely,  nitrogenous  matter,  water,  and  food- 
salts  ;  the  other  contains  the  things  eaten  from 


176  THE   STORY   OF   THE    PLANTS. 

the  air  by  the  plant  in  its  leaves,  and  afterwards 
worked  up  by  it  into  sugars,  starches,  protoplasm, 
and  chlorophyll. 

Stems  are  usually  covered  outside  for  purposes 
of  protection  by  a  more  or  less  thick  integument^ 
which  in  trees  and  shrubs  assumes  the  corky  form 
we  know  as  bark.  Bark  consists  of  dead  and 
empty  cells,  thickened  with  a  lighter  thickening 
matter  than  wood,  and  presenting  as  a  rule  a 
rather  spongy  appearance.  But  beneath  the  bark 
comes  a  distinct  layer  of  living  material,  inter- 
posed between  the  corky  dead  cells  of  the  integu- 
ment and  the  woody  dead  cells  of  the  interior. 
This  living  layer  extends  over  stem,  twigs,  and 
branches  :  it  forms  the  binding  and  connecting 
portion  of  the  entire  plant  community  ;  it  links 
together  in  one  united  whole  the  living  material 
of  the  leaves  and  shoots  with  the  living  material 
of  the  roots  and  rootlets.  It  is  thus  the  stem, 
above  all,  that  gives  to  the  complex  plant  colony 
of  foliage  and  flowers  wlfatever  organic  unity  and 
individuality  it  ever  possesses. 

All  situations,  however,  are  not  alike.  Just  as 
here  this  sort  of  leaf  succeeds,  and  there  that,  so 
in  stems  and  branches,  here  this  form  does  best, 
and  there  again  the  other.  The  shape  of  the  stem 
and  branches,  in  fact,  is  the  shape  of  the  entire 
plant  colony  ;  and  it  is  arranged  to  suit,  on  the 
average  of  instances,  the  convenience  of  all  its 
component  members.  Much  depends  on  the  shape 
of  the  leaves  ;  much  on  the  conditions  of  wind  or 
calm,  shade  or  sunshine. 

Some  plants  are  annuals.  These  require  no 
large  and  permanent  stem  ;  they  spring  from  the 


THE  STEM   AND   BRANCHES.  1 77 

seed  each  year,  like  peas,  or  wheat,  or  poppies; 
they  make  a  stem  and  leaves  ;  they  produce  their 
flowers ;  they  set,  and  ripen,  and  scatter  their 
seed  ;  and  then  they  wither  away  and  are  done 
with  for  ever.  Hundreds  of  such  plants  occur  in 
our  fields  and  gardens.  Even  these  annuals,  how- 
ever, differ  greatly  in  the  amount  of  their  stem  and 
branches.  Some  are  quite  low,  humble,  and  suc- 
culent, like  chickweed  and  sandwort ;  others  have 
tall  and  comparatively  stout  stems,  like  wheat, 
oats,  and  barley,  or  still  more,  like  the  sunflower. 
As  a  rule,  annuals  are  not  very  large ;  but  a  few 
rich  seeds  produce  strong  young  plants  which 
even  within  a  single  year  attain  an  astounding 
size ;  this  is  the  case  with  the  garden  poppy, 
the  tobacco  plant,  and  the  Indian  corn,  and  even 
more  so  with  certain  climbing  annuals,  such  as 
the  gourd,  the  cucumber,  the  melon,  and  the 
pumpkin. 

Many  plants,  however,  find  it  pays  them  better 
to  produce  a  hard  and  woody  stem,  which  lasts 
from  year  to  year,  and  enables  them  to  put  forth 
fresh  leaves  and  shoots  in  each  succeeding  season. 
Among  these,  again,  great  varieties  exist.  Some 
have  merely  a  rather  short  and  stout  stem  with 
many  bundles  of  water-vessels,  as  in  the  pink  and 
the  wallflower.  Their  growth  is  /lerkzccous.  Others, 
however,  produce  that  more  solid  form  of  tissue 
which  we  know  as  wood,  and  which  is  made  up  of 
cells  whose  walls  have  become  much  thickened 
and  hardened.  Among  the  woody  group,  again, 
we  may  distinguish  many  intermediate  varieties, 
from  the  mere  shrub  or  bush,  like  the  heath  and 
the  broom,  through  small  trees  like  the  rhododen- 
dron, the  lilac,  the  hawthorn,  and  the  holly,  to 
such  great,  spreading  monsters  of  the  forest  as 


178  THE   STORY  OF  THE   PLANTS. 

the  oak,  the  ash,  the  pine,  the  chestnut,  and  the 
maple. 

Once  more,  some  plants  produce  an  under- 
ground stem,  and  send  up  from  this  fresh  annual 
branches.  That  is  the  case  with  hops,  with 
meadow-sweet,  and  with  buttercup,  as  well  as 
with  many  of  our  garden  flowers.  When  a  plant 
becomes  perennial,  it  is  a  mere  question  of  its 
own  convenience  w^hether  it  chooses  to  produce  a 
thick  and  woody  stem,  like  trees  and  bushes,  or  to 
lay  up  material  in  undergound  roots,  stocks,  and 
branches,  like  the  potato,  the  dahlia,  the  lilies, 
the  bulbous  buttercup,  the  crocus,  the  iris,  the 
Jerusalem  artichoke,  and  the  meadow  orchis. 

Ordinary  people  divide  most  plants  into  three 
groups — herbs,  shrubs,  and  trees.  But  I  think 
you  will  have  seen  from  what  I  have  just  said 
that  in  every  great  family  of  plants  different 
kinds  have  found  it  worth  while  to  adopt  any  one 
of  these  forms  at  will,  according  to  circumstances. 
Trees,  in  other  words,  do  not  form  a  natural 
group  by  themselves;  any  family  of  plant  may 
happen  to  develop  a  tree-like  species.  Thus  the 
herb-like  clover  and  the  tall  tree-like  laburnum  are 
closely  related  peaflowers.  Most  of  the  com- 
posites are  mere  herbs  or  shrubs,  but  a  very  few 
of  them  in  the  South  Sea  Islands  have  grown  into 
large  and  much-branched  trees.  The  grasses  are 
mainly  herbs  ;  but  some  of  them,  like  the  bam- 
boos, have  developed  tall  and  tree-like  stems, 
much  branched  and  feathery. 

Take  the  single  family  of  the  roses,  for  ex- 
ample, so  familiar  to  most  of  us  ;  some  of  them 
are  mere  annual  weeds,  like  the  tiny  parsley-piert 
that  occurs  as  a  pest  in  every  garden.  Others, 
again,  are  perennials  with  low  tufted  stems,  like  the 


THE   STEM    AND    BRANCHES.  179 

Strawberry ;  or  creeping,  like  the  cinquefoil  ;  or 
rising  into  a  spike,  like  the  burnet  and  the  agri- 
mony. Yet  others  become  scrambling  bushes, 
like  the  blackberry  and  the  raspberry.  In  the 
blackthorn  and  the  hawthorn  the  bush  has  be- 
come more  erect  and  tree-like.  Both  types  of 
growth  occur  in  the  dog-rose  and  many  other 
roses.  The  cherry  attains  the  size  and  stature  of 
a  small  tree.  The  mountain-ash  is  bigger  ;  the 
apple-tree  bigger  still  ;  while  the  pear  often 
grows  to  a  considerable  height  and  much  spread- 
ing, dignity.  These  are  all  members  of  the  rose 
family.  Here,  therefore,  every  variety  of  shape 
and  size  is  well  represented  within  the  limits  of  a 
single  order. 

One  word  must  be  given  to  the  varieties  of 
the  stem.  Sometimes,  as  in  the  oak,  the  trunk  is 
much  branched  and  intricate;  sometimes,  as  in 
the  date-palm,  simple  and  unbranched,  bearing 
only  a  single  tuft  of  circularly  arranged  leaves. 
But  the  most  interesting  in  this  respect  are  the 
climbing  and  twisting  stems,  which  do  not  take 
the  trouble  to  support  themselves,  but  lean  for  aid 
upon  the  trunk  of  some  stronger  and  more  upright 
neighbour.  Stems  of  this  sort  are  familiar  to  us 
all  in  the  hop  and  the  bindweed.  In  other  climb- 
ers the  stems  do  not  twine  to  any  great  extent, 
but  the  plants  support  themselves  by  root-like 
processes,  as  in  ivy,  or  by  tendrils,  as  in  the  vine, 
or  by  twisted  leaf-stalks,  as  in  the  canary  creeper. 
Others  cling  by  means  of  suckers,  as  the  Anipelop- 
sis  Veitchii,  or  hang  by  opposite  leaves,  like  clem- 
atis, or  cling  by  hooked  hairs,  as  is  the  case  with 
cleavers.  In  certain  instances,  such  creeping  or 
climbing  plants  tend  to  become  parasitic — that  is 
to    say,   they   fasten    themselves    by    sucker-like 


l8o  THE   STORY  OF  THE   PLANTS. 

mouths  to  the  bark  of  the  harder  plant  up  which 
they  climb,  and  feed  upon  its  already  elaborated 
juices.  Our  English  dodder  is  an  example  of 
such  a  plant.  It  has  no  leaves  of  its  own,  but 
consists  entirely  of  a  mass  of  red  stems,  bearing 
clusters  of  pretty  pale  pink  flowers. 

Other  plants  show  another  form  of  parasitism. 
Mistletoe  is  one  of  these.  It  fastens  itself  to  a 
poplar  or  an  apple-tree  (very  seldom  an  oak)  and 
sucks  its  juices.  But  it  has  also  green  leaves  of 
its  own,  which  do  real  work  of  eating  and  assimi- 
lating as  well.  It  is  therefore  not  quite  such  a 
parasite  as  the  dodder.  Several  plants  are  simi- 
larly half-parasitic  on  the  roots  of  wheat  and 
grasses.  Among  them  I  may  mention,  as  English 
instances,  the  cow-wheat,  the  yellow  rattle,  and 
the  pretty  little  eyebright. 

Broomrape  is  a  parasite  of  a  different  sort. 
It  grows  on  the  roots  of  clover,  and  has  no  true 
leaves ;  in  their  place  it  produces  short  scales, 
which  contain  no  chlorophyll.  Several  other 
plants  are  also  devoid  of  chlorophyll,  and  there- 
fore cannot  eat  carbonic  acid  for  themselves. 
They  live  like  animals  on  materials  laid  by  for 
them  by  other  plants.  Such  are  toothwort,  a  pale 
rose-coloured  leafless  plant,  with  pretty  spiked 
flowers,  which  grows  by  suckers  on  the  roots  of 
hazel-trees.  The  bird's-nest  orchid,  a  delicate 
brown  plant  with  curious  ghost-like  blossoms, 
feeds  rather  on  the  organised  matter  in  decaying 
leaves  among  thick  beechwoods.  In  this  book  I 
have  purposely  confined  your  attention  for  the 
most  part  to  the  true  green  plants,  which  are  the 
central  and  most  truly  plant-like  type;  but  I 
ought  to  tell  you  now  that  a  great  many  plants, 
especially  among  the  lower  kinds,  behave  in  this 


THE  STEM   AND   BRANCHES.  l8l 

respect  much  more  like  animals :  instead  of 
manufacturing  fresh  starches  and  protoplasms 
for  themselves  from  carbonic  acid,  under  the  in- 
fluence of  sunlight,  they  eat  up  what  has  already 
been  made  by  other  and  more  industrious  species. 
Such  plants  are  retrograde.  They  are  products 
of  degeneracy.  Among  them  I  may  specially 
mention  all  the  fungi,  like  mushrooms,  toadstools, 
mould,  and  mildew,  as  well  as  the  bacilli  and  bac- 
teria, microscopic  and  degenerate  plants  which 
cause  decomposition.  Their  life  is  more  like  that 
of  animals  than  of  true  vegetables. 

In  tropical  forests,  where  the  soil  is  almost 
monopolised  by  huge  spreading  trees,  the  smaller 
plants  have  been  forced  to  secure  their  fair  share 
of  light  and  air  by  somewhat  different  means 
from  those  which  are  common  in  cooler  climates. 
Many  of  them,  without  being  parasitic,  have 
learnt  to  attach  themselves  by  their  roots  to  the 
outer  bark  of  the  trees,  and  so  to  get  at  the 
light,  no  ray  of  which  ever  struggles  through 
the  living  canopy  of  green  in  the  dense  jungle. 
These  plants  have  green  leaves,  and  eat  for 
themselves;  but  they  use  the  boughs  of  their 
host  instead  of  soil  to  root  themselves  in.  Such 
plants  are  technically  known  as  epiphytes.  This 
is  the  mode  of  life  of  most  of  the  handsome 
orchids  cultivated  in  our  conservatories. 

Now  let  us  recapitulate.  The  stem  unites  the 
various  parts  of  the  plant — the  root,  the  leaves, 
the  flowxrs,  the  fruit.  It  conducts  water  and 
nitrogenous  matter  from  the  soil  to  the  foliage. 
It  also  carries  the  manufactured  materials  from 
the  points  where   they  are  made  to    the  points 


l82  THE   STORY   OF   THE    PLANTS. 

where  they  are  wanted  for  the  growth  of  fresh 
organs.  It  supports  and  raises  the  whole  plant 
colony.  Finally,  it  stores  up  material  in  drought 
or  winter,  which  it  uses  for  new  branches,  leaves, 
or  flowers,  when  rain  or  spring  or  favourable 
conditions  in  due  time  come  round  again. 


CHAPTER   XIII. 

SOME    PLANT    BIOGRAPHIES. 

We  have  considered  so  far  the  various  ele- 
ments which  go  to  make  up  the  life  of  plants — 
how  they  eat  and  drink,  how  they  digest  and 
assimilate,  how  they  marry  and  get  fertilised,  how 
they  produce  their  fruit  and  set  their  seeds,  final- 
ly how  they  are  linked  together  in  all  their  parts 
by  stem  and  vessels  into  a  single  community. 
But  up  to  the  present  moment  we  have  con- 
sidered these  elements  in  isolation  only,  as  so 
many  processes  the  union  of  which  makes  up 
what  we  call  the  life  of  an  oak,  or  a  lily,  or  a 
strawberry  plant.  In  order  really  to  understand 
how  all  these  principles  work  together  in  prac- 
tical action,  we  ought  to  take  a  few  specimen  lives 
of  real  concrete  plants,  and  trace  them  through 
direct,  from  the  cradle  to  the  grave,  with  all  their 
vicissitudes.  I  propose,  therefore,  in  this  chapter 
to  give  you  brief  sketches  of  one  or  two  such  life- 
histories  ;  and  I  hope  these  few  hints  may  encour- 
age you  to  find  out  many  more  for  yourself,  by 
personal  study  of  plants  in  their  native  sur- 
roundings. 

''In  their  native  surroundings,"  I   say,  since 


SOME   PLANT   BIOGRAPHIES.  183 

all  life  is  really,  in  Mr.  Herbert  Spencer's  famous 
phrase,  "adaptation  to  the  environment;"  and 
therefore  we  can  only  understand  and  discover 
the  use  and  meaning  of  each  part  or  organ  by 
watching  the  plant  in  its  own  home,  and  among 
the  general  conditions  by  which  it  and  its  ances- 
tors have  always  been  limited.  It  would  be  im- 
possible, for  example,  to  see  the  use  of  the  thick 
outer  covering  of  the  coconut  (from  which  coco- 
nut matting  is  manufactured)  if  we  did  not  know 
that  the  coconut  palm  grows  naturally  by  the  sea- 
shore in  tropical  islands,  and  frequently  drops  its 
fruits  into  the  water  beneath  it.  The  nuts  are 
thus  carried  by  the  waves  and  currents  from  islet 
to  islet ;  and  the  coconut  palm,  which  is  a  deni- 
zen of  sea-sand,  owes  to  this  curious  method  of 
water-carriage  its  wide  dispersion  among  the 
coral-reefs  of  the  Pacific.  But  a  plant  that  is  so 
dispersed  must  needs  make  provision  against 
wetting,  bruising,  and  sinking  in  the  sea ;  and 
since  only  those  coconuts  would  get  dispersed 
over  wide  spaces  of  water  which  happened  to 
possess  a  good  coating  of  fibre,  the  existing  plant 
has  come  to  produce  the  existing  nut  as  we  know 
it — richly  stored  with  food  for  the  young  palm 
while  it  makes  its  first  steps  among  the  barren 
rocks  and  sand-banks,  and  well  provided  by  its 
shaggy  outer  coat  against  the  dangers  of  the  sea, 
the  reefs,  and  the  breakers.  Similarly,  we  could 
never  understand  the  cactus  except  as  a  native 
of  the  dry  plains  of  Mexico.  Or  again,  there  is 
an  orchid  in  Madagascar  with  a  spur  containing 
honey  at  a  depth  of  eighteen  inches.  Now,  no 
European  insect  could  possibly  reach  so  deep  a 
deposit ;  but  a  Madagascar  moth  has  a  gigantic 
proboscis,  exactly  fitted  for  sucking  the  nectary 


184  THE   STORY  OF  THE   PLANTS. 

and  fertilising  the  flowers.  Tlius  no  plant  can 
properly  be  understood  apart  from  its  native 
place;  and  1  have  therefore  confined  myself  for 
the  most  part  in  these  few  brief  life-histories  to 
native  British  plants,  whose  circumstances  and 
surroundings  are  known  to  everybody. 

As  an  example  of  a  very  simple  and  easy  life- 
history,   I   will   take   first  a  little  wayside  weed, 
commonly  known  as  whitlow-grass,  but  called  by 
botanists,  in   their   scientific  Latin,  Draba  ver?ia. 
This  curious  little  herb   is  not  a  grass  at  all  (as 
its  name  might  make  you  think),  but  a  member  of 
the  great  family  of  the  crucifers,  succulent  plants 
with  four  petals  and    six  stamens   in    each   flower, 
to  which    the    cabbage,    the   turnip,  the   sea-kale, 
and  many    other   well-known  garden  species  be- 
long.    But   whitlow-grass  is  not  a  large  and  con- 
spicuous plant  like  any  of  these  ;  it  is  one  of  the 
smallest  and  shortest-lived  of  our  British   weeds. 
It  has  managed  to  carve  itself  out  a  place  in  na- 
ture on  the  dry  banks  and  in  clefts  of  rock  during 
the  few  weeks  in  spring  while  such  spots  are  as 
yet  unoccupied  by  more  permanent  denizens.    The 
herb  starts  from  a  very  minute  seed,  dropped  on 
the  soil  by  the  parent  plant  many  months  before, 
and  patiently  waiting  its  time  to  develop  till  win- 
ter   frosts    are    over,    and   warmer   weather   and 
moisture  begin    to   quicken   its   tiny   seed-leaves. 
As  soon  as  these  have  opened  and  used  up  theii 
very  small  stock  of  internal  nutriment,  the  young 
plant   begins   to   produce   on  its   own   account   a 
rosette  of  little  oblong  green  leaves,  pressed  close 
to  the  ground  for  warmth  and  shelter.     They  eat 
as  they  go,  and  make  fresh   leaves  again  out  of 
the   absorbed   and    assimilated   material.     Direct 
sunshine  falls  upon   them   full  front ;  and  as  no 


SOME   PLANT   BIOGRAPHIES.  1 85 

Other  foliage  overshadows  them  or  competes  in 
their  neighbourhood  for  carbonic  acid,  they  grow- 
apace  into  a  little  tuft  of  spreading  leaves,  about 
half  an  inch  long  or  less,  and  forming  in  the  mass 
a  rough  circle.  For  about  a  week  or  ten  days  the 
little  mouths  go  on  drinking  in  carbonic  acid  as 
fast  as  they  can,  and  manufacturing  it  under  the 
influence  of  sunlight  into  starches  and  proto- 
plasm. At  the  end  of  that  time  they  have  col- 
lected enough  material  to  send  up  a  slender  blos- 
soming stem,  about  an  inch  high  or  more,  bearing 
no  leaves,  but  developing  at  the  top  a  few  tiny 
flower-buds.  These  shortly  open  and  display 
their  flowers,  very  small  and  inconspicuous,  with 
four  wee  white  petals,  each  so  deeply  cleft  that 
they  resemble  eight  to  a  casual  observer.  Inside 
the  petals  are  six  little  active  stamens;  and  inside 
the  stamens  again  a  two-celled  ovary.  The  blos- 
soms are  visited  and  fertilised  on  warm  March 
mornings  by  small  spring  midges,  attracted  by 
the  petals.  They  immediately  set  their  seeds  in 
tne  flat  green  capsule,  ripen  them  rapidly  in  the 
eye  of  the  sun,  and  shed  them  at  once,  the  whole 
life  of  the  plant  thus  seldom  exceeding  three  or 
four  weeks  in  a  favourable  season.  At  the  same 
time,  the  leaves  and  roots  wither,  as  the  material 
they  contained  is  rapidly  withdrawn  from  them, 
and  used  up  in  the  process  of  maturing  the  seeds; 
so  that  as  soon  as  the  fruiting  is  quite  complete, 
the  plant  dies  down,  having  exhausted  itself  ut- 
terly in  the  two  short  acts  of  flowering  and  seed- 
bearing.  During  the  remaining  ten  months  of 
the  year  or  thereabouts,  there  are  no  more  whit- 
low-grasses at  all  in  existence ;  the  species  re- 
mains dormant,  as  it  were,  for  a  whole  long  pe- 
riod in  the  form  of  seeds  lying  buried  in  the  soil, 


1 86       THE  STORY  OF  THE  PLANTS. 

and  only  springs  to  life  again  when  the  return  of 
March  gives  it  warning  that  its  day  has  once 
more  come  round  to  it. 

Contrast  with  this  brief  and  very  spasmodic 
life  of  some  thirty  days  the  comparatively  long 
though  otherwise  extremely  similar  biography  of 
the  Mexican  agave,  commonly  cultivated  in  hot- 
houses in  England,  and  largely  grown  in  the  open 
air  in  the  South  of  Europe  under  the  (incorrect) 
name  of  "American  aloes."  The  agave  is  a  large 
and  strikingly  handsome  lily  of  the  amaryllis  fam- 
ily, about  which  I  have  already  told  you  something 
in  a  previous  chapter.  It  begins  life  as  a  small 
plant,  like  a  London  pride,  springing  from  a  com- 
paratively large  and  richly-stored  seed  on  its  own 
dry  prairies.  Its  leaves,  which  spread  in  a  rosette, 
are  not  unlike  those  of  the  house-leek  in  shape; 
they  are  very  large,  thick,  and  fleshy.  But  as  they 
grow  in  the  hot  and  dry  climate  of  Mexico,  an 
almost  desert  country,  with  a  very  small  rainfall, 
they  have  a  particularly  hard  outer  skin,  so  as  to 
prevent  undue  evaporation ;  and  they  are  pro- 
tected against  the  attacks  of  herbivorous  animals 
by  being  spiny  at  the  edges,  and  ending  in  a  stout 
and  dagger-like  point  of  the  most  formidable  de- 
scription. The  centre  of  the  plant  is  occupied  by 
a  sort  of  sheath  of  leaves,  concealing  the  growing 
point.  For  several  years  the  round  bunch  of  outer 
leaves  grows  bigger  and  bigger,  till  it  attains  a 
diameter  of  ten  or  fifteen  feet  at  the  base,  seem- 
ing still  like  a  huge  rosette,  with  hardly  any  visi- 
ble stem  to  speak  of.  Meanwhile  these  huge  leaves 
are  busy  all  the  time,  eating  and  assimilating,  and 
storing  up  manufactured  food-stuffs  as  hard  as 
they  can  in  their  thick  and  swollen  bases.  After 
six   or  seven   years  in   their  native   climate,   the 


SOME   PLANT   BIOGRAPHIES.  1 87 

plant  feels  itself  in  a  position  to  send  up  a  flower- 
ing stalk,  which  is  formed  from  the  materials  al- 
ready laid  by  in  these  immensely  thick  and  richly- 
stored  leaf  bases.  The  stalk  springs  from  the 
middle  of  the  central  leaf^sheath.  In  a  very  few 
weeks  the  agave  has  sent  up  from  this  point  a 
huge  flowering  scape,  twenty  or  thirty  feet  high, 
and  a  foot  or  fifteen  inches  thick  at  the  bottom. 
On  this  scape  it  produces  with  extraordinary  ra- 
pidity a  vast  number  of  large  and  showy  yellow 
flowers,  which  look  not  unlike  an  enormous  can- 
delabrum, with  many  divided  branches.  The  plant 
is  enabled  to  produce  this  immense  flowering  stem 
and  these  numerous  flowers  in  so  short  a  period, 
because  it  draws  upon  its  large  store  of  elaborated 
material  for  the  purpose.  But  as  the  flowering 
stem  rises,  and  the  flowers  unfold,  and  the  big 
fruits  and  seeds  develop  and  ripen,  the  leaves  be- 
low grow  gradually  flaccid  and  empty;  and  their 
bases  shrink,  being  depleted  of  their  store  of  valu- 
able food-stuffs;  so  that  by  the  time  the  seeds  are 
ripe,  the  whole  plant  is  used  up,  having  exhausted 
itself,  like  the  tiny  whitlow-grass,  in  the  act  of 
fruiting.  It  then  dies  down  altogether,  and  never 
recovers,  though  new  plants  or  offsets  usually  de- 
velop at  its  base  from  side  buds,  after  the  original 
agave  has  begun  to  wither.  In  English  hothouses 
it  takes  thirty  or  forty  years  before  the  agave  has 
collected  enough  material  to  send  up  a  stem  and 
flower;  hence  the  common  exaggeration  that  it 
needs  a  hundred  years  for  "  the  blossoming  of  an 
aloe." 

As  a  familiar  example  of  a  very  different  kind 
of  perennial  plant,  we  may  take  our  English  beech- 
tree.  The  beech  sets  out  in  life  as  a  tender  young 
seedling,  which  grows  from  a  good-sized  triangular 


1 88       THE  STORY  OF  THE  PLANTS. 

nut,  whose  cotyledons  are  well-stored  with  food- 
stuffs for  its  early  development.  As  the  nut  ger- 
minates, the  cotyledons  open  out,  become  flat  and 
green,  like  thick  fleshy  leaves,  and  begin  to  absorb 
carbonic  acid  from  the  air,  which  they  work  up  at 
once  with  the  material  supplied  by  the  tiny  root 
into  protoplasm  and  chlorophyll.  In  the  angle 
between  them  a  young  shoot  develops,  which  soon 
puts  forth  delicate  blades  of  true  foliage  leaves; 
and  these  in  turn  grow  and  assimilate  material 
under  the  influence  of  sunlight.  In  the  first  year 
the  little  beech-tree  is  but  a  tiny  sapling,  with  a 
short  stem,  already  woody ;  but  year  after  year, 
this  stem  grows  higher,  branches  out  and  divides, 
and  slowly  clothes  itself  in  the  smooth  grey  bark 
characteristic  of  the  species.  The  particular  way 
in  which  it  branches  is  this :  each  autumn  there  is 
formed  at  the  base  of  every  leaf  a  winter  bud, 
long  and  brown,  and  covered  with  close  scales, 
which  enable  it  to  survive  the  cold  of  winter. 
When  spring  comes  round  again,  each  one  of 
these  buds  develops  in  turn  into  a  leafy  branch, 
so  that  (accidents  excepted)  there  are  as  many 
new  branches  or  twigs  every  year  as  there  were 
leaves  on  the  tree  in  the  preceding  season.  The 
young  leaves  and  branches  emerge  slowly  and 
cautiously  from  the  buds  in  spring,  for  fear  of 
frost ;  they  are  protected  at  first  by  certain  scaly 
brown  coverings  known  as  stipules.  Gradually, 
however,  as  the  weather  grows  warmer,  the  stip- 
ules fall  off,  and  display  the  tender  green  leaves, 
exposed  to  the  air,  but  still  folded  together.  As 
soon  as  they  can  trust  the  season,  however,  the 
leaves  unfold,  though  they  are  still  thickly  covered 
at  the  edges  by  protective  hairs,  which  afterwards 
fall  off,  but  which  guard  the  fresh  green  chloro- 


SOME   PLANT   BIOGRAPHIES.  189 

phyll  in  the  cells  just  at  first  both  from  chilly 
winds  and  from  the  injurious  effect  of  excessive 
sunlight.  Year  after  year  the  beech-tree  grows 
by  so  subdividing  and  adding  branch  to  branch; 
while  its  stem  increases  by  yearly  rings  of  growth, 
till  it  attains  at  length  considerable  dimensions. 

During  many  such  seasons  of  growth  the 
beech-tree  does  not  flower;  all  the  material  it 
manufactures  through  the  summer  in  its  large 
flat  leaves  it  lays  by  in  its  stem  to  supply  the 
young  shoots  and  branches  at  the  beginning  of 
the  subsequent  season.  But  at  last,  when  it  has 
reached  the  height  and  girth  of  a  small  tree,  it 
begins  to  store  up  protoplasm  and  starches  for 
blossom  also.  Some  of  its  buds  are  now  leaf- 
buds,  but  some  are  flower-buds,  produced  in 
autumn,  and  held  over  till  April.  In  the  spring 
these  flower-buds  lengthen  and  produce  bunches 
of  blossoms,  which  we  call  catkins,  some  of  them 
males,  and  some  females,  but  both  sexes  growing 
on  the  same  tree  together.  They  bloom,  like 
most  other  catkins,  in  the  early  spring,  while  the 
leaves  are  still  very  little  developed,  so  as  to  pre- 
vent the  foliage  from  interfering  with  the  carriage 
of  the  pollen.  The  males  are  produced  in  hang- 
ing clusters  an  inch  or  so  long;  while  the  females 
stand  up  in  small  globular  bunches,  on  erect 
flower -stems.  They  are  wind  -  fertilised  ;  and 
shortly  after  flowering,  the  male  catkins  drop 
off  entire,  having  done  their  life-work,  while  the 
females  swell  out  into  the  familiar  husks  or  four- 
valved  cups,  containing  each  some  two  or  three 
triangular  nuts,  richly  stored  with  food-stuffs. 

The  agave  only  flowers  once,  and  then  dies 
down,  exhausted.  But  the  beech  goes  on  flower- 
ing for  many  years  together,  and  grows  mean- 


190  THE   STORY   OF   THE   PLANTS. 

while  larger  and  larger  in  bulk,  its  trunk  increas- 
ing in  girth,  and  becoming  buttressed  at  the  base, 
so  as  to  support  the  large  head  of  branches  and 
the  dense  mass  of  foliage.  For  the  boughs  are 
so  arranged  that  a  great  crown  of  leaves  is  ex- 
posed in  summer  to  the  sun  and  air  at  the  outer 
circumference  of  the  dome-shaped  mass ;  and  in 
this  way  every  leaf  gets  its  fair  share  of  light  and 
carbon,  and  interferes  as  little  as  possible  with 
the  work  of  its  neighbours.  Old  beeches  will 
grow  to  more  than  100  feet  in  height,  and  live 
for  probably  three  or  four  centuries.  At  last, 
however,  their  protoplasm  grows  old  and  seems 
to  get  enfeebled ;  the  trunk  decays,  and  the  entire 
tree  falls  first  into  dotage,  then  dies  by  slow  de- 
grees of  pure  senility. 

The  common  vetch  is  another  familiar  plant 
whose  life-history  introduces  to  us  some  totally 
different  yet  interesting  features.  It  belongs  to 
the  wide-spread  family  of  the  peaflowers,  to  which 
I  have  already  more  than  once  alluded,  and  it 
takes  its  origin  from  a  comparatively  large  and 
rich  round  seed,  not  unlike  a  pea,  whose  cotyle- 
dons are  well  stored  with  supplies  of  starch  and 
other  food-stuffs.  It  sends  up  at  first  a  short 
spreading  stem,  which  twines  or  trails  over  sur- 
rounding plants,  developing  as  it  goes  very  curi- 
ous leaves  of  a  compound  character.  Each  leaf 
consists  of  five  or  six  pairs  of  leaflets,  placed  op- 
posite one  another  on  the  common  stalk  in  the 
feather-veined  fashion.  But  the  four  or  five  leaf- 
lets at  the  end  of  each  leaf-stalk  do  not  develop 
any  flat  blade  at  all,  and  are  quite  unleaflike  in 
appearance :  they  are  transformed,  indeed,  into 
long,  thin  tendrils,  which  catch  hold  of  neigh- 
bouring  branches    or    stems    of    grasses,    twine 


SOME   PLANT   BIOGRAPHIES.  191 

spirally  round  them,  and  so  enable  the  vetch  to 
climb  up  bodily  in  spite  of  its  weak  stem,  and  raise 
its  leaves  and  flowers  to  the  air  and  the  sunlight. 

At  the  base  of  every  leaf,  again,  you  will  find, 
if  you  look,  two  arrow-shaped  appendages,  which 
block  the  way  up  the  stem  towards  the  developing 
flowers  for  useless  creeping  insects  such  as  steal 
the  honey  without  assisting  fertilisation.  On  each 
appendage  is  a  curious  black  spot,  the  use  or 
function  of  which  is  not  apparent  while  the  blos- 
soms are  in  the  bud.  But  after  a  few  weeks' 
growth,  the  vetch  begins  to  produce  solitary 
flowers  in  the  angle  of  each  upper  leaf  ;  flowers 
of  the  usual  pea-blossom  type,  but  pink  or  red- 
dish purple,  and  handsome  or  attractive.  These 
flowers  contain  abundant  honey  to  allure  the 
proper  fertilising  insects.  Just  as  they  open, 
however,  the  black  spot  on  the  arrow-headed 
appendages  of  the  lower  leaves,  in  whose  angles 
there  are  no  flowers,  begins  also  to  secrete  a  little 
drop  of  honey. 

What  is  the  use  of  this  device  ?  Well,  if  you 
watch  the  vetch  carefully,  you  will  soon  see  that 
ants,  enticed  by  the  smell  of  honey  in  the  open- 
ing flowers,  crawl  up  the  stem  in  hopes  of  steal- 
ing it.  But  ants,  as  we  know,  are  thieves,  not 
fertilisers.  As  soon  as  they  reach  the  first  black 
spot,  they  stop  and  lick  up  the  honey  secreted 
by  the  gland,  and  then  try  to  pass  on  to  the  next 
appendage  above  it.  But  the  arrow-shaped  barbs, 
turned  back  against  the  stem,  block  their  further 
progress ;  and  even  if  they  manage  to  squeeze 
themselves  through  with  an  effort,  they  are  met 
just  above  by  another  honey-gland  and  another 
barrier  in  the  shape  of  a  second  arrow-shaped  ap- 
pendage.    No  ant  ever  gets  beyond  the  third  or 


192       THE  STORY  OF  THE  PLANTS. 

fourth  barricade  ;  the  device  is  efficient :  the  vetch 
thus  offers  blackmail  to  creeping  thieves  in  the 
shape  of  stem-honey,  in  order  to  guard  from  their 
depredations  the  far  more  valuable  and  useful 
honey  in  the  flowers,  which  is  intended  to  attract 
the  fertilising  insects. 

When  the  purple  flowers  have  in  due  time 
been  fertilised,  they  produce  long  narrow  pods, 
each  containing  about  a  dozen  round  pea-like 
seeds.  As  the  pods  ripen,  the  plant  shrivels  up, 
and  usually  dies  away,  leaving  only  the  ripe  seeds 
to  represent  its  kind  through  the  winter.  But 
sometimes,  in  damp  and  luxuriant  autumns,  the 
stem  struggles  through  the  winter  to  a  second 
season,  and  flowers  again  in  the  succeeding  sum- 
mer. We  express  this  fact  as  a  rule  by  saying 
that  the  vetch  is  usually  an  annual,  but  occasion- 
ally a  biennial. 

With  most  annuals,  such  as  wheat  or  sunflower, 
the  whole  strength  of  the  plant  is  used  up  in  the 
production  of  seed  ;  and  as  soon  as  the  seed  is  set, 
the  plant  dies  immediately.  Where  annuals  have 
the  sexes  on  separate  plants,  however,  the  male 
plants  die  as  soon  as  they  have  shed  their  pollen, 
their  task  being  thus  complete;  while  the  females 
live  on  till  their  seed  has  ripened. 

Common  coltsfoot  is  another  well-known  plant 
whose  life-history  shows  some  points  of  great 
interest.  It  grows  in  the  first  instance  from  a 
feathery  fruit,  one-seeded  and  seed-like,  which  is 
carried  by  the  wind,  often  from  a  great  distance. 
These  flying  fruits  alight  at  last  upon  some  patch 
of  bare  or  newly-turned  soil,  such  as  the  bank  of 
a  stream  where  there  has  been  lately  a  landslip, 
or  the  side  of  a  railway  cutting.  These  bare  sit- 
uations alone  suit  the  habits  of  the  baby  coltsfoot ; 


SOME   PLANT   BIOGRAPHIES.  193 

if  the  fruit  happens  to  settle  on  a  light  soil,  al- 
ready thickly  covered  with  luxuriant  vegetation, 
it  cannot  compete  against  the  established  possess- 
ors. But  the  winged  fruits,  being  dispersed  on 
every  side,  enable  many  young  plants  to  start 
well  in  life  on  the  poor  stiff  clays  which  best  suit 
the  constitution  of  this  riverside  weed.  The  seed- 
ling grows  fast  in  such  circumstances,  and  soon 
produces  large  angular  leaves,  very  broad  and 
thick,  which  in  the  adult  plant  have  often  a  di- 
ameter of  five  or  six  inches.  They  are  green 
above,  where  they  catch  the  sunlight  and  devour 
carbonic  acid;  but  underneath  they  are  covered 
with  a  thick  white  wool,  which  is  there  for  a  cu- 
rious and  interesting  purpose.  The  damp  clay 
valleys  and  river  glens  where  coltsfoot  lives  by 
choice  are  filled  till  noon  every  day  with  mist  and 
vapour;  and  heavy  dew  is  deposited  there  every 
night  through  the  summer  season.  Now,  if  this 
dew  were  allowed  to  clog  the  evaporation  pores 
or  stomata  on  the  leaves  of  coltsfoot,  the  plant 
would  not  be  able  to  raise  water  or  proceed  with 
its  work  except  for  perhaps  a  few  hours  daily. 
To  prevent  this  misfortune,  the  under  side  of  the 
leaves  is  thickly  covered  with  a  white  coat  of  wool, 
on  which  no  dew  forms,  and  off  which  water  rolls 
in  little  round  drops,  as  you  have  seen  it  roll  off  a 
serge  table-cloth.  By  this  ingenious  device  the 
coltsfoot  manages  to  keep  its  evaporation  pores 
dry  and  open,  in  spite  of  its  damp  and  moisture- 
laden  situation.  One  may  say,  indeed,  that  every 
point  in  the  structure  of  every  plant  has  thus 
some  special  purpose;  indeed,  one  large  object  of 
the  study  of  plants  is  to  enable  us  to  understand 
and  explain  such  hidden  purposes  in  the  economy 
of  nature. 
13 


194  THE   STORY   OF   THE   PLANTS. 

During  its  early  life,  once  more,  the  young 
plant  of  coltsfoot  is  constantly  engaged,  like  the 
whitlow-grass  and  the  agave,  in  laying  by  mate- 
rial for  its  future  flowering  season.  But  it  does 
not  lay  by,  as  they  do,  in  its  expanded  leaves  or 
other  portions  of  its  body  visible  above  ground ; 
instead  of  that,  it  puts  forth  a  creeping  under- 
ground stem  or  root-stock,  which  pushes  its  way 
sideways  through  the  tough  clay  soil,  often  for 
several  feet,  and  sends  up  at  intervals  groups  of 
large  roundish  leaves,  such  as  I  have  already  de- 
scribed, to  work  above  ground  for  it.  You  might 
easily  take  each  such  group  for  a  separate  plant, 
unless  you  dug  up  the  root-stock  and  saw  that 
they  were  really  the  scattered  foliage  of  one  sub- 
terranean stem,  which  grows  horizontally  instead 
of  upward.  During  the  summer  the  coltsfoot  lays 
by  in  this  buried  root-stock  quantities  of  rich  ma- 
terial for  next  year's  leaves  and  for  its  future 
flowers.  In,  winter  the  leaves  die  down,  and  you 
see  not  a  trace  of  the  plant  above  ground.  But 
in  very  early  spring,  as  soon  as  the  soil  thaws, 
certain  special  buds  begin  to  sprout  on  the  under- 
ground stem,  and  send  up  tall  naked  scapes  or 
flower-stems,  usually  growing  in  tufts  together, 
and  each  crowned  by  a  single  large  fluffy  yellow 
flower-head.  These  stems  are  covered  below  by 
short  purplish  scales;  and  their  purple  colouring 
matter  enables  them  to  catch  and  utilise  to  the 
utmost  the  scanty  sunshine  that  falls  upon  the 
plant  in  chilly  March  weather.  For  this  particu- 
lar colouring  matter  has  the  special  property  of 
converting  the  energy  in  rays  of  light  into  heat 
for  warming  the  plant.  The  scape  is  also  wrapped 
up  in  a  sort  of  cottony  wool,  which  helps  to  keep 
it  warm;   and    the   unopened   flower-head    turns 


SOME   PLANT   BIOGRAPHIES.  195 

downward  at  first  for  still  further  safety  against 
chill  or  injury.  These  various  devices  enable  the 
coltsfoot  to  blossom  earlier  in  the  season  than 
almost  any  other  insect-fertilised  flower,  and  so  to 
monopolise  the  time  and  attention  of  the  first 
flower-haunting  March  insects. 

Coltsfoot  is  a  composite  by  family ;  so  its 
flowers  are  collected  together  into  a  head,  after 
the  ancestral  fashion,  and  enclosed  by  an  invo- 
lucre which  closely  resembles  a  calyx.  But  the 
type  of  flower-head  differs  somewhat  from  that 
in  any  of  the  composite  plans  I  have  hitherto 
described  for  you,  because  its  outer  florets  are 
not  flat  and  ray-shaped,  but  strap-like  or  needle- 
shaped.  The  inner  florets,  however,  are  bell- 
shaped,  and  much  like  those  of  the  common  daisy. 
The  naked  scapes,  each  resembling  to  the  eye  a 
shoot  of  asparagus,  and  each  .crowned  by  a  single 
fluffy  yellow  flower-head,  are  familiar  objects  on 
banks  or  railway  cuttings  in  the  first  days  of 
spring;  I  have  known  them  open  as  early  as  the 
i2th  of  January,  in  sunny  weather.  But  they  grow 
entirely  without  leaves,  and  are  produced  at  the 
expense  of  the  material  laid  up  in  the  underground 
stem  by  last  season's  foliage.  They  blossom,  are 
fertilised,  set  their  seeds,  turn  into  heads  of  white 
feathery  down,  and  produce  ripe  fruits  which 
blow  away  and  get  dispersed,  all  before  the  leaves 
begin  to  appear  at  all  above  the  soil.  Thus  you 
never  can  see  the  foliage  and  flowers  together;  it 
is  only  by  close  observation  that  you  can  discover 
for  yourself  the  connection  between  the  heads  of 
yellow  flowers  which  come  up  in  early  spring,  and 
the  groups  of  large  angular  woolly  leaves  which 
follow  them  in  the  same  spots  much  later  in  the 
season. 


196       THE  STORY  OF  THE  PLANTS. 

The  life-history  of  the  coltsfoot  introduces  us 
also  to  another  conception  which  we  must  clearly 
understand  if  we  wish  to  know  anything  about 
many  plant  biographies.  I  have  said  already  that 
parts  of  one  and  the  same  coltsfoot  plant  might 
easily  be  mistaken  for  separate  individuals ;  and, 
indeed,  if  the  stem  gets  severed,  particular  groups 
of  leaves  may  live  on  as  such,  in  two  or  more  dis- 
tinct portions.  This  leads  us  on  to  the  considera- 
tion of  a  great  group  of  plants  like  the  common 
wild  strawberry,  in  which  a  regular  system  of  sub- 
division exists,  and  in  which  new  plants  are  ha- 
bitually produced  by  offsets  or  runners,  as  well  as 
by  seedlings.  Such  a  method  of  increase  is  to 
some  extent  a  survival  into  higher  types  of  the 
primitive  mode  of  reproduction  by  subdivision. 

A  strawberry  plant  grows  in  the  first  instance 
from  a  seed,  which  was  embedded  in  a  carpel  or 
seed-like  fruitlet  on  the  ripe  red  swollen  receptacle 
which  we  commonly  call  a  strawberry.  This  seed 
germinates,  and  produces  a  seedling,  which  puts 
forth  small  green  leaves,  divided  into  three  leaflets 
each  at  the  end  of  a  long  and  slender  leaf-stalk. 
As  it  grows  older,  however,  besides  its  own  tufted 
perennial  stem  or  stock,  it  sends  out  on  every  side 
long  branches  or  runners,  which  are  in  fact  hori- 
zontal or  creeping  stems  in  search  of  new  root- 
ing place's.  These  stems  run  along  the  ground 
for  some  inches,  and  then  root  afresh.  At  each 
such  rooting-point,  the  plant  sends  up  a  fresh 
bunch  of  leaves,  which  gradually  grows  into  a 
distinct  colony,  by  the  decay  of  the  intermediate 
portion  or  runner.  Again,  this  new  plant  itself 
in  turn  sends  forth  runners  in  every  direction  all 
round  it ;  so  that  often  the  ground  is  covered  for 
yards  by  a  network  of  strawberry  plants,  all  ulti- 


SOME   PLANT   BIOGRAPHIES.  197 

mately  derived  from  a  single  seedling.  Theoret- 
ically, we  must  regard  them  all  as  severed  parts 
of  one  and  the  same  plant,  accidentally  divided 
from  the  main  stem,  since  only  the  union  of  two 
different  parents  can  give  us  a  totally  distinct  in- 
dividual. But  practically  they  are  separate  and 
independent  plants,  competing  with  one  another 
thenceforth  for  food,  soil,  and  sunshine. 

A  great  many  plants  are  habitually  propagated 
in  such  indirect  ways,  as  well  as  by  the  normal 
method  of  flowering  and  seeding.  Indeed,  it  is 
difficult  to  separate  the  two  processes  of  mere 
growth,  as  shown  in  budding  or  branching,  and 
reproduction  by  subdivision,  as  shown  in  the 
springing  of  saplings  from  the  roots  or  stem,  the 
production  of  runners,  the  division  of  bulbs,  and 
the  rooting  of  suckers.  I  will  therefore  give  here 
a  few  select  instances  of  these  frequent  incidents 
in  the  life-history  of  various  species. 

The  tiger-lilies  of  our  gardens  produce  little 
dark  buds,  often  called  bulbils,  in  the  angles  of 
their  foliage  leaves.  These  buds  at  last  fall  off 
and  root  themselves  in  the  soil,  forming  to  all  ap- 
pearance independent  plants.  Much  the  same 
thing  happens  with  many  English  wild-flowers. 
For  example,  in  the  plant  known  as  coral-root 
(allied  to  the  cuckoo-flower)  little  bud-bulbs  are 
formed  in  the  angles  of  the  leaves,  which  drop  on 
the  damp  soil  of  the  woods  where  the  plant  grows, 
and  there  develop  into  new  individuals.  In  this 
last-named  case  the  plant  seldom  sets  its  fruit  at 
all,  the  reproduction  being  almost  entirely  carried 
on  by  means  of  the  bulbils.  Such  instances  sug- 
gest to  us  the  pregnant  idea  that  a  seed  is  noth- 
ing more  than  a  bud  or  young  shoot,  to  whose 
making  two   separate  parents  have  contributed. 


198  THE   STORY   OF  THE   PLANTS. 

There  is,  in  short,  no  essential  difference  between 
the  two  processes  of  growth  and  reproduction. 

Again,  in  the  common  lesser  celandine  the  root- 
stock  emits  a  large  number  of  tiny  pill-like  tubers, 
which  grow  and  lay  by  rich  material  underground 
(derived  from  the  leaves)  during  the  summer  sea- 
son. In  the  succeeding  spring,  however,  each  of 
these  tubers  develops  again  into  a  separate  plant, 
in  a  way  with  which  the  familiar  instance  of  the 
potato  has  made  us  familiar.  In  the  crocus, 
once  more,  and  many  other  bulbous  plants,  sev- 
eral small  bulbs  are  produced  each  year  by  the 
side  of  the  large  one,  and  these  smaller  bulbs  are 
of  course,  strictly  speaking,  mere  branches  of  the 
original  crocus-stem.  But  they  grow  separate  at 
last,  by  the  decay  or  death  of  the  central  bulb, 
and  themselves  in  turn  produce  at  their  side  yet 
other  bulbs,  which  become  the  centres  of  still 
newer  families.  We  may  parallel  these  cases  with 
those  of  trees  whose  boughs  bend  down  and  root 
in  the  ground  so  as  to  become  in  time  independ- 
ent individuals;  or  with  runners  like  those  of  the 
strawberry  and  the  creeping  buttercup,  which  root 
and  grow  afresh  into  separate  plantlets. 

Sometimes  still  more  curious  things  happen  to 
plants  in  the  way  of  reproduction  by  subdivision. 
There  is  an  English  pondweed,  for  example,  which 
grows  in  shallow  pools  liable  to  be  frozen  over  in 
severe  winters.  As  cold  weather  approaches,  the 
top  of  the  growing  shoots  in  this  particular  pond- 
weed  break  off  of  themselves,  much  as  leaves  do 
at  falling  time.  But  they  break  off  with  all  their 
living  material  still  preserved  within  them  undis- 
turbed; and  they  then  sink  and  retire  to  the 
unfrozen  depths  of  the  pond,  where  they  remain 
unhurt  till    spring  comes  round  again.     This  is 


SOME    PLANT   BIOGRAPHIES.  199 

just  what  the  frogs  and  newts  and  other  animal  in- 
habitants of  the  pond  do  at  the  same  time  to  pre- 
vent getting  frozen.  Next  year  the  severed  tops 
send  out  roots  in  the  soft  mud  of  the  bottom,  and 
grow  up  afresh  into  new  green  pondweeds. 

It  is  therefore  impossible  to  make  any  broad 
line  of  distinction  in  this  way  between  what  may 
be  considered  as  modes  of  individual  persistence 
in  the  self-same  plants,  and  what  may  be  regarded 
as  modes  of  reproduction  by  subdivision.  Some 
plants,  like  couch-grass  and  elm,  are  almost  always 
surrounded  by  young  shoots  which  may  ultimate- 
ly become  to  all  intents  and  purposes  independent 
individuals;  while  others,  like  corn -poppy  or 
Scotch  fir,  never  produce  any  offsets  or  suckers. 
In  the  meadow  orchids  each  plant  produces 
every  summer  a  second  tuber  by  the  side  of  the 
old  one;  and  from  the  top  of  this  tuber  the  next 
year's  stem  arises  in  due  time  with  its  spike  of 
flowers.  Here  we  may  fairly  regard  the  tuber  as 
a  simple  means  of  persistence  in  the  plant  itself ; 
there  is  nothing  we  could  possibly  call  reproduc- 
tion. But  in  many  lilies  the  older  bulbs  produce 
numerous  small  branch  bulbs  at  their  sides ;  and 
these  younger  bulbs  may  become  practically  in- 
dependent, each  of  them  sending  up  in  the  course 
of  time  its  own  stem  and  its  own  spike  of  flowers. 

Even  when  the  main  trunk  of  a  tree  is  dead, 
through  sheer  old  age,  it  often  happens,  as  in  the 
elm  and  birch,  that  the  roots  send  up  fresh  young 
shoots,  which  may  grow  again,  and  prolong  the 
life  of  the  plant  indefinitely.  In  stone-crops  and 
other  succulent  herbs,  which  grow  in  very  dry  and 
desert  situations,  the  merest  fragment  of  a  stem, 
dropped  on  moist  soil,  will  send  out  roots  and 
grow  afresh  into  a  new  individual.     Cactuses  and 


200  THE   STORY   OF   THE    PLANTS. 

Other  desert  plants  have  often  to  resist  immense 
drought,  and  therefore  possess  extraordinary  vital- 
ity in  this  way.  They  will  grow  again  from  tjie 
merest  cut  end  under  favourable  conditions. 

These  few  short  hints  as  to  the  life-history  of 
various  plants  in  different  circumstances  will  serve 
to  show  you  how  vast  is  their  variety.  Every  plant, 
indeed,  has  endless  ways  and  tricks  of  its  own; 
and  every  point  in  its  structure,  however  unob- 
trusive, has  some  purpose  to  serve  in  its  domestic 
economy.  Thus  the  ivy-leaved  toad-flax,  which 
grows  on  dry  walls,  has  straight  flower-stalks, 
which  become  bent  or  curved  when  the  flowering 
is  over.  Why  is  this  ?  Well,  the  plant  has  ac- 
quired the  habit  of  bending  round  its  flower-stalk 
after  the  blossoming  season,  because  it  cannot 
sow  its  seeds  on  the  bare  stone,  so  it  hunts  about 
diligently  for  a  crevice  among  the  mortar  into 
which  it  proceeds  to  insert  its  capsule,  so  that 
the  seedlings  may  start  fair  in  a  fit  and  proper 
place  for  their  due  germination.  So,  too.  the 
subterranean  clover,  growing  on  close-cropped 
hillocks  much  nibbled  over  by  sheep,  where  its 
pods  of  rich  seeds  would  be  certainly  devoured 
if  exposed  on  a  long  stalk  like  that  of  other 
clovers,  has  developed  a  few  abortive  corkscrew- 
like blossoms  in  the  centre  of  its  flower-head,  by 
whose  aid  the  whole  group  of  pods  burrows  its 
way  spirally  into  the  soil  beneath  ;  so  that  the 
plant  thus  at  once  escapes  its  herbivorous  ene- 
mies, and  sows  its  own  seed  for  itself  automat- 
ically. -It  would  be  impossible  in  our  space  to  do 
more  than  thus  briefly  indicate  by  two  or  three 
examples  the  immense  number  and  variety  of 
these  special  adaptations.  Every  plant  has  hun- 
dreds of  them.     There  is  not  a  tiny  hair  on  the 


SOME   PLANT   BIOGRAPHIES.  20I 

surface  of  a  flower,  not  a  spot  or  a  streak  in  the 
blade  of  a  leaf,  not  a  pit  or  depression  on  the  skin 
of  a  seed,  that  has  not  its  function.  And  close 
study  of  nature  rewards  us  most  of  all  for  our 
trouble  in  this,  that  it  reveals  to  us  every  day 
some  delightful  surprise,  forces  on  our  attention 
some  hitherto  unsuspected  but  romantic  relation 
of  structure  and  purpose. 

I  will  mention  but  one  more  case  as  a  typical 
example.  There  exists  as  a  rule  a  definite  rela- 
tion between  the  shape  and  arrangement  of  the 
leaves  in  plants,  and  the  shape  and  arrangement 
of  the  roots  and  rootlets,  with  regard  to  water- 
supply.  Each  plant,  in  point  of  fact,  is  like  the 
roof  of  a  house  as  respects  the  amount  of  rain 
which  it  catches  and  drains  away ;  and  it  is  im- 
portant for  each  that  it  should  utilise  to  the  ut- 
most its  own  particular  supply  of  drainage  or  rain 
water.  Hence  you  will  find  that  some  plants,  like 
the  dock,  have  large  channelled  leaves,  with  a  leaf- 
stalk traversed  by  a  depression  like  a  drainage 
runnel :  plants  of  this  type  carry  off  all  the  water 
that  falls  upon  them  towards  the  centre,  inwards. 
But  such  plants  have  always  also  a  descending 
tap-root,  which  instantly  catches  and  drinks  up 
the  water  poured  by  the  drainage  system  of  the 
leaves  towards  the  middle  of  the  plant.  In  other 
plants,  again,  however,  with  round  leaf-stalks  and 
outward  pointed  leaves,  the  water  that  falls  upon 
the  foliage  drains  outward  towards  the  circum- 
ference ;  and  in  all  such  plants  the  roots,  instead 
of  descending  straight  down,  are  spreading  and 
diffused,  so  as  to  go  outward  towards  the  point 
where  the  water  drips  on  them.  Moreover,  in 
this  latter  case  it  is  found,  on  digging  up  the 
plant    carefully,  that  the  absorbent   tips  of  the 


202  THE   STORY   OF   THE    PLANTS. 

rootlets  are  clustered  thickest  about  the  exact 
spots  where  the  leaves  habitually  drop  the  water 
down  upon  them.  Every  plant  is  thus  to  some 
extent  a  catchment-basin  which  utilises  its  own 
rainfall  :  it  collects  rain  for  itself,  and  conducts 
it  by  a  definite  system  of  pipes  and  channels  to 
the  precise  spots  in  the  soil  where  it  can  best  be 
sucked  up  for  the  plant's  own  purposes. 

On  the  other  hand,  while  every  part  of  every 
plant  is  thus  minutely  arranged  for  the  common 
advantage,  every  species  of  plant  and  animal 
fights  only  for  its  own  hand  against  all  comers. 
Nature  is  therefore  one  vast  theatre  of  plot  and 
counterplot.  The  parasites  prey  on  the  vegeta- 
tive kinds;  the  vegetative  kinds  respond  in  turn 
by  developing  checks  to  counteract  the  parasites. 
The  squirrels  produce  sharper  and  ever  sharper 
teeth  to  gnaw  through  the  nutshells ;  the  nut- 
trees  retaliate  by  producing  for  their  part  thicker 
and  ever  thicker  shells  to  baffle  the  squirrels. 
And  this  play  and  by-play  goes  on  unceasingly 
from  generation  to  generation;  because  only  the 
cleverest  squirrels  can  ever  get  enough  nuts  to 
live  upon  ;  and  only  the  hardest-shelled  and 
bitterest-rinded  nuts  can  escape  the  continual 
assaults  of  the  squirrels.  In  order,  therefore, 
really  to  understand  the  structure  and  life  of  any 
one  species,  we  should  have  to  know  in  the  mi- 
nutest detail  all  about  its  native  conditions,  its 
soil,  its  surroundings,  its  allies,  its  hired  friends, 
its  blackmailing  foes,  its  exterminating  enemies. 
Such  exhaustive  knowledge  of  the  tiniest  weed  is 
clearly  impossible ;  but  even  the  little  episodes 
we  can  pick  out  piecemeal  are  full  of  romance,  of 
charm,  and  of  novelty. 


THE   PAST   HISTORY  OF  PLANTS.  203 

CHAPTER   XIV. 

THE    PAST    HISTORY    OF    PLANTS. 

I  PROMISED  some  time  since  to  return  in  due 
season  to  the  question  why  plants,  as  a  rule,  ex- 
hibit distinct  kinds  or  species^  instead  of  merging 
gradually  one  into  another  by  imperceptible  de- 
grees. This  problem  is  generally  known  as  the 
problem  of  the  origin  of  species.  You  might  per- 
haps expect  (since  plants  have  grown  and  de- 
veloped, as  we  have  seen,  one  out  of  the  other) 
that  they  would  consist  at  present  of  an  unbroken 
series,  each  melting  into  each,  from  the  highest 
to  the  lowest.  This,  however,  is  not  really  the 
case;  they  form  on  the  contrary  groups  of  dis- 
tinct kinds  :  and  the  reason  is,  that  natural  selec- 
tion acts  on  the  whole  in  the  opposite  direction. 
It  tends  to  make  plants  group  themselves  into 
definite  bodies  or  species,  all  alike  within  the  body, 
and  well  marked  off  from  all  others  outside  it. 

Here  is  the  way  this  arrangement  comes 
about.  As  situations  and  circumstances  vary,  a 
form  is  at  last  arrived  at  in  each  situation  which 
approximately  fits  the  particular  circumstances. 
This  form  may  perhaps  vary  again  in  other  situ- 
ations, and  give  rise  to  individuals  better  adapted 
to  the  second  set  of  circumstances.  But  just  in 
proportion  as  such  individuals  surpass  in  adap- 
tation one  another  will  they  live  down  the  less 
adapted.  Hence,  the  intermediate  forms  will 
tend  to  perish,  and  the  world  to  be  filled  in  the 
end  with  groups  of  plants,  each  distinct  from 
others,  and  each  relatively  fixed  and  similar 
within  its  own  limits. 


204  THE   STORY   OF   THE   PLANTS. 

At  all  times,  and  in  all  places,  this  process  of 
variation  3.nd  adaptation  is  continually  going  on; 
new  kinds  are  being  formed,  and  intermediates 
are  dying  out  between  them.  For  the  interme- 
diates  are  necessarily  less  adapted  than  the  older 
form  to  the  old  conditions,  and  than  the  newer 
form  to  the  new  ones. 

Moreover,  when  any  great  point  of  advantage 
is  once  gained  by  a  kind,  it  tends  to  go  on  and  be 
preserved,  while  variations  in  other  parts  con- 
tinue uninterrupted.  Thus,  the  first  composite 
plant  (to  take  a  concrete  example)  gained  by  the 
massing  of  its  flowers  into  a  compact  head  :  and 
it  then  became  a  starting-point  for  fresh  develop- 
ments, each  of  which  maintained  the  massed  flow- 
er-head,  with  its  ring  of  united  stamens,  while 
adding  to  the  type  some  fresh  point  of  its  own, 
which  specially  adapted  it  to  a  particular  situ- 
ation. So,  too,  the  first  peaflower  gained  by  the 
peculiar  form  of  its  oddly-shaped  corolla,  and 
therefore  became  the  ancestor  of  many  separate 
kinds,  each  of  which  retains  the  general  pea-like 
type  of  blossom,  while  differing  in  other  respects 
as  widely  from  its  neighbours  as  gorse  and  clO" 
ver,  peas  and  laburnum,  broom  and  vetches,  scar- 
let-runners and  lupines.  A  group  of  kinds,  so  de- 
rived from  a  common  progenitor,  but  preserving 
throughout  one  or  more  of  that  progenitor's  pe- 
culiarities, while  differing  much  in  other  respects 
among  themselves,  is  called  a  family.  Thus  we 
speak  of  the  family  of  the  peaflowers,  the  family 
of  the  roses,  the  family  of  the  lilies,  the  family  of 
the  orchids.  Each  family  may  include  several 
minor  groups,  known  as  genera  (in  the  singular,  a 
genus)  ;  and  each  such  genus  may  further  include 
several  distinct  kinds  or  species. 


THE   PAST   HISTORY  OF   PLANTS.  205 

For  example,  all  the  peafiow er  /ami'/y  are  dis- 
tinguished by  their  possession  of  a  peculiar  blos- 
som whose  corolla  consists  of  a  standard,  a  keel, 
and  two  wings,  like  sweet-pea  or  broom.  This 
family  contains  several  genera^  one  of  which  is 
that  of  the  clovers,  including  certain  peaflowers 
which  have  learned  to  mass  their  blossoms  into  a 
roundish  head,  and  have  trefoil  leaves,  and  very 
few  seeds  in  the  short  seed-pod.  The  clovers, 
again,  are  subdivided  into  species  or  kinds,  such 
as  purple  clover,  Dutch  clover,  hop  clover,  and 
hare's-foot  clover  ;  in  Britain  alone,  we  have 
twenty-one  such  distinct  species  or  kinds  of  clo- 
ver. You  will  see  at  once  that  this  method  of 
grouping  by  ancestral  forms  enables  us  largely  to 
reconstruct  the  history  of  each  particular  plant 
or  animal. 

Why  don't  these  kinds  cross  freely  with  one 
another,  and  so  produce  an  endless  set  of  puzzling 
hybrids  ?  Well,  they  do  occasionally ;  and  such 
mongrel  forms  often  show  us  every  possible  vari- 
ation between  the  two  parents.  But  this  can  only 
happen  when  the  parent  stocks  are  very  close  to 
one  another ;  and  even  then,  the  hybrids  tend  to  die 
out  rapidly.  Why  ?  Because  each  of  the  parents 
is  better  adapted  to  a  particular  situation  ;  the 
hybrid  usually  falls  between  two  stools,  and  gets 
killed  down  accordingly.  It  cannot  stand  the 
competition  of  the  true  species.  New  kinds,  how- 
ever, may  sometimes  take  their  rise  from  chance 
hybrids,  which  happen  to  possess  some  combina- 
tion of  advantages. 

Thus  plants  in  the  mass,  as  we  see  them 
around  us  at  the  present  day,  are  divisible  into 
several  well-marked  groups,  some  of  which  are 


2o6  THE   STORY  OF   THE   PLANTS. 

now  dominant  or  leading  orders,  while  others  are 
hardly  more  than  mere  belated  stragglers  or  loi- 
tering representatives  of  types  once  common,  but 
now  outstripped  in  the  race  by  younger  competi- 
tors. I  cannot  close  without  briefly  describing  to 
you  the  main  divisions  of  such  orders  or  groups, 
as  now  accepted  by  modern  botanists. 

The  widest  distinction  of  all  between  plants 
is  that  Which  marks  off  the  simpler  and  earlier 
forms,  which  are  wholly  composed  of  cells,  from 
the  higher  and  stem-forming  types,  which  are 
also  provided  with  systems  of  vessels  and  woody 
tissue.  The  first  class  is  known  as  Cellular 
Plants;  the  second  class  as  Vascular  Plants. 
These  are  the  greatest  and  most  general  divisions. 

The  Cellular  Plants  comprise  many  sorts, 
from  the  simple  one-celled  types  which  float  freely 
in  water,  up  to  the  relatively  high  and  complex 
seaweeds,  which  produce  large  fleshy  fronds,  and 
often  display  a  considerable  division  of  labour 
between  their  various  parts  and  organs.  Still,  as 
most  of  them  live  in  water,  either  fresh  or  salt, 
and  wave  freely  about  in  the  liquid  that  surrounds 
them,  they  have  no  need  of  an  elaborate  system 
of  conducting  vessels,  because  every  part  can 
drink  in  water  and  dissolved  food-salts  from  the 
neighbouring  pond,  sea,  or  river.  Still  less  have 
they  any  necessity  for  a  woody  stem,  which  would 
only  be  a  disadvantage  to  them  in  stormy  weather. 
Hence  most  of  the  cellular platits  (with  certain  ex- 
ceptions to  be  noted  hereafter)  are  water-weeds; 
while  most  of  the  vascular  plants  (with  other  ex- 
ceptions to  be  similarly  treated)  are  land  plants. 
In  particular  trees  and  shrubs,  the  highest  forms 
of  plant  life,  are  invariably  terrestrial. 

Various   successive   stages    of   these   cellular 


THE   PAST   HISTORY   OF   PLANTS.  207 

plants  may  be  briefly  described  in  rough  outline. 
First  of  all  we  get  the  simple  one-celled  plant,  the 
lowest  type  of  all,  consisting  of  a  single  mass 
of  protoplasm,  generally  with  chlorophyll,  sur- 
rounded by  a  cell-wall.  Next  above  these  come 
the  hair-like  water-weeds,  which  consist  of  rows  of 
such  simple  cells,  placed  end  to  end  in  single  file, 
one  in  front  of  another,  like  pearls  in  a  necklace. 
These  kinds  are  many-celled,  but  each  cell  is  here 
in  contact  with  two  others  only,  one  below,  and 
one  above  it.  Thirdly,  we  get  the  flat  leaf-like 
water-weeds,  which  have  thin  green  fronds,  com- 
posed of  a  single  broad  sheet  of  cells,  not  a  hair- 
like row;  each  cell  has  here  many  cells  around  it, 
but  all  lie  in  one  plane;  the  sheet  is  only  one  cell 
thick  ;  it  does  not  spread  abroad  in  more  than 
two  directions.  Lastly,  we  get  the  ordinary  thick- 
fronded  seaweed,  in  which  sheets  of  cells,  many 
layers  deep,  grow  in  divided  masses  on  rope-like 
bases,  and  closely  resemble  to  the  eye  true  vas- 
cular plants  with  stems,  leaves,  and  branches. 

Most  of  these  cellular  plants,  when  they  pos- 
sess green  chlorophyll,  are  known  as  algcE. 

There  are  several  low  forms  of  plants,  how- 
ever, which  do  not  possess  chlorophyll,  but  live 
at  the  expense  of  other  plants,  exactly  as  animals 
do.  These  are  generally  known  in  the  lump  as 
fungi.  Many  of  them  are  terrestrial.  The  dis- 
tinction, however,  is  not  a  genealogical  one.  Cel- 
lular plants  of  various  grades  have  often  taken, 
time  after  time,  to  this  lower  parasitic  or  carrion- 
eating  habit ;  and  though  they  therefore  resemble 
one  another  externally  m  their  absence  of  green 
colour,  in  their  usual  whiteness  and  fleshiness,  and 
in  their  mushroom-like  substance,  they  do  not 
really  form  a  natural  class ;  their  resemblance  is 


2o8  THE   STORY   OF   THE    PLANTS. 

due  to  their  habits  only.  In  short,  we  call  any 
cellular  plant  a  fungus,  if  instead  of  supporting 
itself  by  green  cells,  it  has  adopted  the  trick  of 
living  on  organised  material  already  laid  up  by 
other  plants  or  animals. 

Among  these  fungus-like  plants,  again,  some 
of  the  simplest  and  lowest  are  the  celebrated  bac- 
teria, which  are  one-celled  organisms,  living  in 
stagnant  or  putrid  fluids,  and  also  in  the  bodies 
and  blood  of  diseased  animals.  They  answer 
among  fungi  to  the  one-celled  algce.  Many  of 
them  cause  infectious  diseases  ;  such  are  the  bacilli 
of  diphtheria,  typhus,  cholera,  consumption,  srrjall- 
pox,  and  influenza.  Surrounded  by  a  suitable  nu- 
tritious fluid,  these  tiny  parasitic  plants  increase 
with  extraordinary  and  fatal  rapidity.  Though 
they  are  really  one-celled,  and  reproduce  by  cell- 
division,  they  often  hang  together  in  rude  lumps 
or  oiusters  which  simulate  to  some  extent  the 
many-celled  bodies.  In  this  book,  however,  where 
we  have  concentrated  our  attention  mainly  on  the 
true  or  green  plants,  I  have  not  thought  it  well 
to  dwell  at  any  length  on  the  habits  or  structure 
of  these  animal-like  organisms. 

Another  well-known  group  of  small  fungus- 
like plants  is  that  which  contains  the  yeast-fungus, 
a  one-celled  plant,  which  reproduces  by  budding. 

The  higher  fungi  are  many-celled,  and  often 
possess  well-marked  organs  for  different  purposes. 
They  answer  rather  to  the  seaweeds  and  higher 
algcE.  Familiar  examples  are  the  common  moulds, 
which  form  on  jam,  dead  fruit,  and  other  decay- 
ing material.  Some  of  them,  like  the  smut  of 
wheat  and  oats,  are  parasitic  on  growing  plants, 
and  most  dangerous  enemies  to  green  vegetation. 
The  highest  fungi  are  the  groups  which  include 


THE   PAST   HISTORY  OF   PLANTS.  209 

the  mushroom,  the  puff-ball,  and  all  those  oth- 
er large  and  curiously-shaped  forms  commonly 
lumped  together  in  popular  language  under  the 
name  of  toadstools.  Their  anatomy  and  physiol- 
ogy is  extremely  complex. 

To  recapitulate;  Cellular  Plants  belong  to 
two  main  types ;  those  which  contain  chlorophyll^ 
and  live  like  plants  by  eating  and  assimilating 
carbon  under  the  influence  of  sunshine;  these  are 
generally  grouped  together  in  a  rough  class  as 
ALG^  :  and  those  which  contain  no  chlorophyll^  but 
live,  like  animals,  by  using  up  or  destroying  the 
carbon-compounds  already  stored  up  by  green 
plants ;  these  are  generally  grouped  together  in 
a  rough  class  as  fungl 

The  lichens  form  a  curious  mixed  group,  whose 
strange  habits  cannot  here  be  described  at  any 
adequate  length ;  they  are  not  so  much  separate 
plants  as  united  colonies  of  algce  and  fungi,  in 
which  the  green  alga  does  the  main  work  of  col- 
lecting food,  while  the  parasitic  fungus,  increasing 
with  it  at  the  same  rate,  eats  it  up  in  part,  while 
contributing  in  turn  in  various  ways  to  the  gen- 
eral good  of  the  compound  community.  This  is 
therefore  hardly  a  case  of  pure  destructive  para- 
sitism, but  rather  one  of  a  co-operative  society 
banded  together  on  purpose  for  mutual  advan- 
tage. 

The  mosses  and  liverworts,  once  more,  show 
us  an  intermediate  stage  between  the  true  cel- 
lular and  the  true  vascular  plants.  They  have 
a  rudimentary  stem,  and  beginnings  of  vessels. 
They  have  also  leaves,  or  organs  equivalent  to 
them ;  and  they  display  the  first  approach  to 
something  like  flowers. 
14 


2IO  THE   STORY  OF  THE   PLANTS. 

The  Vascular  Plants,  again,  which  are  char- 
acterised by  the  possession  of  special  vessels  for 
the  conveyance  of  sap  and  organised  material, 
and  by  the  presence  of  more  or  less  woody  fibres, 
are  divisible  into  two  main  groups — the  floiver- 
less,  and  \.\\t.  flowering. 

The  floiverless  group  of  Vascular  Plants  are 
mainly  represented  by  the  ferns  and  horsetails. 
These  were  at  one  time  the  leading  vegetation  of 
the  entire  world,  far  outnumbering  in  kinds  all 
the  rest  put  together.  But  they  have  now  been 
lived  down  by  the  flowering  plants,  which  at  pres- 
ent compose  the  main  mass  of  the  plant  aristoc- 
racy. 

The  flowering  plants,  once  more,  fall  into  two 
main  groups ;  the  small  but  widespread  group  of 
naked-seeded  plants^  including  the  cycads,  pines, 
firs,  cypresses,  and  yews ;  and  the  very  large 
group  of  fruit-bearing  plants,  including  almost  all 
the  kinds  of  herb,  shrub,  bush,  or  tree  familiarly 
known  to  you,  as  well  as  almost  all  those  various 
plants  with  which  we  have  busied  ourselves  in  this 
little  volume.  You  will  thus  see  that  the  vast 
majority  of  species  in  the  vegetable  kingdom  be- 
long to  small  and  relatively  inconspicuous  orders. 
Indeed,  for  the  most  part,  we  habitually  disregard 
the  cellular  plants,  thinking  only  of  the  vascular ; 
while  among  the  vascular  themselves,  again,  we 
disregard  the  flowerless,  thinking  only  of  the 
flowering;  and  among  the  flowering  kinds,  we 
concentrate  our  attention  as  a  rule  on  the  fruit- 
producing  group  (in  the  botanical  sense  of  the 
word)  and  neglect  the  naked-seeded.  In  short, 
we  usually  confine  our  attention  to  the  highest 
division  of  the  highest  group  of  the  highest  half 
of   the    vegetable    kingdom.      The    rest   are    for 


THE   PAST   HISTORY  OF   PLANTS.  211 

US  mere  inconspicuous  mosses,  moulds,  or  sea- 
weeds. 

The  fruit-producing  group  of  flowering  plants 
are  finally  divided  into  the  dicotyledons  and  the 
monocotyledons,  whose  chief  differences  I  have  al- 
ready pointed  out  to  you.  And  to  complete  our 
picture  of  this  infinite  hierarchy,  the  dicotyledons, 
once  more,  are  divided  into  various  families,  such 
as  the  buttercups,  the  roses,  the  crucifers,  the 
composites,  the  labiates,  the  umbellates,  the  saxi- 
frages, and  the  catkin-bearers.  The  buttercup 
family,  in  particular  (to  select  a  single  group),  is 
further  divisible  into  genera,  such  as  buttercup, 
marsh-marigold,  larkspur,  anemone,  clematis,  and 
aconite;  while. the  buttercup  genus  (to  take  one 
only  among  these)  comprises  in  turn  a  vast  num- 
ber of  species,  such  as  the  water-crowfoot,  the 
ivy-leaved  crowfoot,  the  meadow  buttercup,  the 
bulbous  buttercup,  the  lesser  celandine,  the  goldi- 
locks, and  so  on  for  pages.  Similarly,  the  mono- 
cotyledons are  divided  into  various  families,  such 
as  the  orchids,  lilies,  grasses,  and  sedges :  the 
families  are  divided  into  many  genera;  and  each 
genus  into  several  species.  The  infinite  variety 
of  circumstances  is  such  that  each  type  goes  on 
varying  and  varying  for  ever  in  order  to  fit  itself 
for  the  endless  situations  it  is  called  upon  to  fill, 
and  the  endless  diversity  in  the  accidents  of  cli- 
mate or  soil  or  position  that  it  may  chance  to 
come  across.  Thus  we  have  in  England  more 
than  a  hundred  different  kinds  of  grasses,  each 
specially  adapted  for  some  one  particular  situa- 
tion. 

Only  the  closest  individual  study  can  give  any 
adequate  idea  of  this  immense  diversity  of  plants 
in  nature. 


212  THE   STORY  OF  THE   PLANTS. 

The  geological  history  of   the  world   shows   us 
that  the  development  of  plants  has  been  slow  and 
progressive.     In   the   earliest   rocks  (of  which  an 
account  is  given  in  another  volume  of  this  series), 
we  get  few  traces  of  any  plants  but  the  lowest :  so 
that  at  that  time  it  is  probable  none  but  seaweeds 
and  their  like  existed — cellular  plants  which  con- 
tain hardly  any  parts  solid  enough  for  preserva- 
tion.    By  the   age  when  the  coal  was  laid  down, 
however,  ferns,  horsetails,  and  many  gigantic  ex- 
tinct plants  with  solid  stems  had  begun  to  exist ; 
but   few  or   no   flowering  plants,  except  conifers, 
had  yet  been  developed.     Later  still  came  the  true 
flowering   plants,  with   covered   seeds,  at   first   in 
'  simple  and  antiquated  forms,  but  -becoming  more 
complex  as  birds,  mammals,  and  flying  insects  of 
the  flower-haunting  types  were  developed  side  by 
side  with  them  to  visit  and   fertilise  them  or  to 
disperse  their  seeds.     Succulent  fruits,  of  course, 
could   only  arise  when  tribes  of  fruit-eaters  had 
been  evolved  to  assist  them  ;  while  such  special 
bee-fertilised  types  as  the  sage  group,  and  such 
complex  forms  as  the  orchids  and  composites,  re- 
quiring the  aid  of  highly-developed  insects,  are 
of  extremely  recent  evolution.     Plant  and  animal 
life  have  continually  reacted  upon  one  another. 

Whoever  has  been  interested  in  the  study  of 
plants  by  this  little  book  may  be  glad  to  know 
what  is  the  best  way  of  continuing  his  acquaint- 
ance with  the  subject  in  future.  Nothing  gives 
one  such  a  grasp  of  the  facts  of  botany  and  of 
life  in  general  as  careful  study  of  the  plants  which 
grow  in  one's  own  country.  Students  in  the 
British  Isles  should  therefore  buy  a  copy  of 
Bentham  and  Hooker's  British  Flora,  and  seek  by 
the  aid  of  the  key  at  its  beginning  to  identify  for 


THE   PAST   HISTORY  OF   PLANTS.  213 

themselves  every  flowering  plant  they  come  across 
in  our  woods  and  meadows.  American  students 
should  get  in  like  manner  Asa  Gray's  Manual  of 
Botany.  In  the  course  of  identifying  all  the 
plants  you  find,  you  will  begin  to  understand  the 
nature  of  plant  life  and  the  course  of  plant  evo- 
lution in  a  way  that  is  quite  impossible  through 
any  mere  book-reading.  Buy  also  a  simple  platy- 
scopic  lens,  and  a  sharp  penknife  to  assist  you  in 
dissection.  Armed  with  these  simple  but  useful 
tools,  you  will  soon  make  rapid  and  solid  prog- 
ress in  the  knowledge  of  nature. 

For  further  and  more  detailed  information  on 
the  laws  of  plant  life,  you  cannot  do  better  than 
consult  Kerner  and  Oliver's  Natural  History  of 
Plants.,  which  sets  forth  in  full  an  immense  num- 
ber of  interesting  and  curious  facts,  in  language 
comprehensible  to  any  attentive  and  careful  stu- 
dent. 


INDEX. 


A. 

Acacias,  50,  173. 

Aconite,  winter,  93,  94. 

Adaptation,  204. 

Agave,  Mexican,  "  Century 
Plant,"  186. 

Air,  food  furnished  by,    14,  34. 

Alder,  131. 

Algje,  207. 

Amaryllids,  113. 

Anemones,  71,  153. 

Angelica,  138. 

Animals,  agency  of,  in  seed  dis- 
tribution, 12;  necessity  of 
plants  to,   14. 

Annuals,  51,  176. 

Anthers,  80. 

Apple,  156,  179. 

Arrowhead,  108,  iii. 

Artichoke,  144. 

Arum,  common,  71,  120;  white, 
"  calla  lily,"   123. 

Ash,  proportion  in  wood,  3^ 

Ash,  150. 

Asparagus,  113. 

Asphodel,  113,  136. 

Aster,  145,  146. 

B. 

Bachelors'  buttons,  93. 
Bacilli,  208. 
Bacteria,  208. 
Balsam,  garden,  152. 
Bamboos,  133,  178. 
Banana,  157. 
Barberry,  156. 
Bark,  68,  176. 
Barley,  133. 
Bean,  97. 
Beech,  132,  187. 


Bees,  colony  system  of,  Tj. 
Beets,  160. 
Begonias,  106. 
Birch,  132,  150. 
Birdsfoot-trefoil,  98. 
Birds,    as    an    agent    in    the    fer- 
tilisation of  flowers,  102. 
Blackberry,  155. 
Bladderwort,  68. 
Bracts,   143. 
Branches,    161.  ■ 
Breadfruit,  157. 
Broom,  97,  173. 
Broomrape,  180. 
Budding,  51. 
Bulbs,  52. 
Burdock,  144. 

Burnet,  great,   128;   salad-,   126. 
Bur-reed,  129. 
Buttercup,  71,  89,  149. 


Cactus,  50,  183,  199. 

Calla  lily,  123,  148. 

Calla,  marsh-,  123. 

Calyx,  83,  128. 

Campion,   red,  30,  31,  83;  white, 

31- 
Canterbury  bell,  98. 
Carbonic    acid,    food    of    plants, 

14,  34,  59. 
Carnivorous  plants,  63. 
Carpel,  79,  80,  94,  in. 
Carrot,  138,  145. 
Catchflies,  65. 
Catkins.  130,  148. 
Celandine,   lesser,    71,   93,    198. 
Celery,  138. 
Cells,  plant,  2(),  172. 
Cellular  plants,  206. 


215 


2l6 


THE    STORY   OF   THE    PLANTS. 


Cellular   tissue   of   plants,   43. 

Centaury,  144. 

"  Century  plant,"  186. 

Cherry,  1=55. 

Chervil,  138. 

Chlorophyll,   19,  26,  35,  37,  50,  54, 

58,  180,  207. 
Chrysanthemum,  146. 
Cinerarias,  146. 
Cleavers,  158. 
Clematis,  153. 
Clover,  139. 
Coal,  16. 
Coconut,  183. 
Colony,    plant    compared    to    a, 

IT- 
Colours  in  flowers,   11,  30,  80,  83, 

86,   88,   90,   94,    102,    no,    124. 
Coltsfoot,  192. 
Columbine,  94,  95. 
Composites,  140,  204. 
Compound  leaves,  44. 
Convolvulus,  83,  98. 
Coral  root,  197. 
Coreopsis,  146. 
Cornflowers,  145. 
Corolla,  83;   tutular,  98. 
Cotton,  154. 
Cotyledons,  161. 
Cow-parsnip,  138,  145. 
Cowslip, 137. 
Crocus,  71,  115,  198. 
Cross-fertilisation,   31,   84,   87,  91, 

106,  118,  135. 
Cucumber,  107,  157. 


Daffodil,  71,  114,  136. 

Dahlia,  139,  145,  146. 

Daisy,  139,  145. 

Dandelion,  139,  148,  152. 

Dicotyledons,    115,    161,    166,   211. 

Dissected  leaves,  45. 

Division,     reproduction     by,     21, 

74- 
Dodder,  180. 
Dog-rose,  96. 
Dogwood,  156. 
Draba  verna,  184. 

E. 

Elderberry,  156. 

Elm,  150. 

Energy,  plants  as  storers  of,  16. 

Entire  leaves,  45. 


Epiphytes,  181, 
Eucalyptus,  50. 
Euphorbia,  50. 
Evaporation,  168. 
Evolution,  26. 

F. 

Families,  204. 
Ferns,  210. 
Fig,  158. 
Figwort,  102. 
Flowering-rush,  no,  in. 
Flowers,  '/2)^  85,  162, 
Forget-me-not,  137. 
Fox-glove,  loi,  136,  137. 
Fritillary,  113. 
Fruit,  II,  149,  154. 
Fungi,  58,  207, 


Gardenia,  32. 

Genera,  204. 

Geological   plants,   212. 

Geranium,   scarlet,   104;   wild,  96. 

Germination,  161. 

Gladiolus,  116. 

Gorse,  47,  71,  97,  98. 

Govird,  157. 

Grape,  157. 

Grasses,   44,    130,    132,   160,   178. 

Groundsel,  135. 


H. 

Harebell,  98,  113. 

Haw,  156. 

Hazel,  131. 

Head,  137. 

Heath,  98,  137. 

Hemlock,  138,  145. 

Hemp,  108. 

Herbaceous  plants,  177. 

Herb-bennet,  158. 

Herb-Robert,  96. 

Heredity,  22,  32.' 

Holly,  46,  156. 

Honey,   11,  30,  90,   102. 

Honey-guides     in     flowers,     103, 

112. 
Honeysuckle,  156. 
Hops,  108. 
Hornbeam,  132. 
Houndstongue,  158. 
Humming-birds,  102. 
Hyacinth,   70,   71,   112,    136,  150. 
Hybrids,  205. 
Flydrogen,  15. 


INDEX. 


217 


T. 

Indian   corn,   133,   177. 
Inlioration,  135. 
Insect-eating  plants,  63. 
Insect  fertilisation,   11,  30,  85,  8(. 

87,    94,    102,    109,    116,    119,    122 

125,    136. 
Insects,   choice  of  honey,  90. 
Involucre,  143. 
Iris,  IIS,  116,  150. 


Jasmine,  32. 
Jonquils,  71. 


J. 


Laburnum,  97,  178. 

Land-plants,    origin    of,    29. 

Larkspur,  94,  95,  150. 

Laurel,  common,  30.  • 

Leaves,  53,  78,  162,  201 ;  func- 
tions of  the,  33;  shapes  of, 
37;  origin  of,  48;  structure  of, 
169;   falling  of,   51. 

Lemon,  157. 

Lichens,  209. 

Lilac,  136. 

Lilies,   44,    III,    136. 

Lilium  auratum,  112,  136. 

Lily-of-the-valley.    113,    137. 

Lime,  150. 

Lines  in  floM^ers,  103. 

Liverworts,  209. 

Lobed  leaves,  45. 

Lupine,  97,  98. 

M. 
Magnolia,  136. 
Mallow,  96,  135. 
Mango,  157. 
Manures,  61. 
Maples,  150. 

Marriage  of  plants,  10,  73. 
Marsh-marigold,    71,    93,    150. 
Medlar,  156. 
Melons,  107,  157. 
Millet,  133- 

Mistletoe,    108,    156,    180. 
Monkey-plants,  loi. 
Monkshood,  94,  96. 
Monocotyledons,  115,161,  166,  211. 
Mosses,  209. 
Mountain-ash,  179. 
Mulberry,    157. 

N. 
Narcissus,  114. 
Nasturtium,  40,  103.1' 


"  Natural  selection,"  27,  32. 
Nectarine,  156. 
Nepenthes,  67. 
Nettle,  128. 

Night-fiowering  plants,  31. 
Nitrogen,  how  plants  obtain,   57, 

61,  63,  72. 
Nuts,  158,  160,  202. 


Oak,  132. 

Odours  in  flowers,  31. 

Old  man's  beard,  153. 

Onion,  113. 

Orange,  157. 

Orchids,   104,   116,   180,   183. 

Origin  of  plants,  14,  26. 

Ovaries,  inferior,  113;  develop- 
ment of  the,  94,  96,  in;  com- 
pound, III. 

Ovule,  the,  10,  23,  76,  80,  82,  86. 

Oxygen,  15,  59. 

P. 

Palmate  leaves,  41. 

Parallel    veined    leaves,    114,    144. 

Parasitic    plants,    180,    202,    208. 

Peach,  155. 

Peaflowers,  97,   150,   160,   178,  204. 

Pear,  156,   179. 

Perennials,  51,  165. 

Perianth,  no. 

Petals,  83,  88. 

Phosphorus,   how   plants   obtain, 

57,  61. 
Pme-apple,  157. 
Pinnate  leaves,  41. 
Pistil,  the,   10,   76,  86. 
Pitcher  plants,  66. 
Plum,  155. 

Pollen,    10,   23,   76,   81,   86. 
Pollen-masses    of    orchids,    117. 
Pollination,  reproduction  by,   10, 

Pomegranate,  157. 

Poppy,   28,   96,    150,   151,    160,    177. 

Potash,  61. 

Potato,    70,    160. 

Primrose,  99. 

Protoplasm,  57,  75. 

Pumpkin,  107,  157. 


Ranunculus,  turban. 
Raspberry,  155. 
Reproduction,  21,  73. 


93- 


2l8 


THE  STORY   OF  THE   PLANTS. 


Ribs,  of  leaves,  40. 
Rice,  133. 

"  Robin    Hood,"   30, 
Root-pressure,  168. 
Roots,  54,  jz,  101. 
Rose  family,  156. 
Rose-hip,  156. 
Roses,  178. 

Rotation  of  crops,  62. 
Runners,  62,  196. 


Sage,  loi. 

Salad-burnet,  ii6. 

Salvias,    loi;    scarlet,    149. 

Samphire,  138. 

Sand-box  tree,  152. 

Sap,   169,   175. 

Scabious,  137,  139,  142. 

Seaweed,  207. 

Seeds,   dispersion  of,   12,   149. 

Self-fertilisation,  85,  135. 

Sepals,  83. 

"  Setting  "  melons,  107. 

Sex  in  plants,  'JZ',  105. 

Shaddock,  157. 

Shepherd's  purse,  135. 

Side-saddle  plant,  66. 

Smuts,  208. 

Snap-dragon,  loi. 

Snowdrop,   71,    113. 

Snowflake,   summer,    114. 

Soil,   food   furnished   by   the,   34, 

59- 
Solomon's  seal,   113,   137. 
Spathe,  120,  148. 
Species,   origin,   203,   205. 
Squill,  113. 

Stamens,   10,  "jf),  79,  80,  86,   125. 
Stapelia,  102. 

Star-of-Bethlehem,  113,  136. 
Stems,  161. 
Stephanotis,  32. 
Stigma,  81. 
Stomata,  171,  193. 
Strawberry,  155,  196. 
"  Struggle   for   Existence,"   2T. 
Style,  the,  82. 
Suckers,  62. 

Sulphur,  how  plants  obtain,  57. 
Sun,   source  of  energy,   16. 
Sundew,  62,. 

Sunflower,   139,  145,   146,   147. 
Sweet-pea,  97. 
Sweet-william,  137. 


Teasel,  65. 
Thistle,  143. 
Thistledown,  152. 
Thorns,  46. 

Tiger  lily,    104,    112,   197. 
Toad-flax,    ivy-leaved,    200. 
Toothed  leaves,  45. 
Toothwort,  180. 
Tropseolum,  40. 
Tuberose,  z^^  ii3»  "^Z^^- 
Tubular  corolla,  98. 
Tulip,  70,  no,  113,  136. 
Turk's-cap  lily,  112. 
TurnipSj  160. 


U. 


Umbel,  137,  145, 


"  Variation,"   28,   32,   47,   204. 
Vascular  plants,  206,  210. 
Vascular  tissue,  40,  49. 
Veins  of  leaves,  41. 
Venus's  fly-trap,  63. 
Vetch,  97,  190. 
Vines,  179. 
Violet,  104. 

W. 

Water-crowfoot,  39,  93,  173. 
Water,    food    furnished    by;    14, 

34- 
Water-lily,   88,   136,   173. 
Water  plant,  earliest,  22,  26. 
Water-plantain,  109,  in. 
Wheat,  133. 
Whitlow-grass,  184. 
Whortleberry,  156. 
Willows,  132. 
Wind,    as    seed    carrier,    12,    ()2, 

150. 
Wind-fertilisation,  11,  30,  124. 
Wood,  165,  166. 


Yarns,  160. 


Zinnia,  146. 


Z. 


THE    END. 


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